Retelistica
Echipamente IT
Cand aducem in discutie termenul de ❤️retelistica, ne gandim la ❤️echipamente IT. Va oferim o gama variata de produse pentru retelistica. Fie ca sunteti in cautarea unui router, a unui switch, a unui repetor, a unui NAS sau pur si simplu doriti sa aflati care sunt cele mai noi produse lansate de marii giganti din industrie, aici gasiti ceea ce aveti nevoie.
lei4,603.65
NAS QNAP 464eU 4-Bay, CPU Intel Celeron N5105/N5095 4-core/4-thread processor (burst max. 2.9 GHz), RAM: 8GB DDR4 (not expandable), HDD: 2.5"/3.5" SATA 6Gbps (neincluse), LAN: 2 x 2.5GbE (2.5G/1G/100M/10M), 2 x M.2 2280 PCIe, USB3.2 Gen2: 2 x Ty
Mikrotik CRS305-1G-4S+OUT FIBERBOX PLUS, Procesor: 800 MHz dual core, Sistem operare: RouterOS v7 / SwOS, 256Mb RAM, 16MB Flash,
lei917.52
Mikrotik CRS305-1G-4S+OUT FIBERBOX PLUS, Procesor: 800 MHz dual core, Sistem operare: RouterOS v7 / SwOS, 256Mb RAM, 16MB Flash, POE in 802.3af/at 42-57 V, interfata: 1 x 10/100/1000, 4 x SFP, Wwatherproof: IP66.
Wireless Access Point Mikrotik C52IG-5HAXD2HAXD-TC, hAP aX2 AX1800, WI- FI6, Standarde wireless: Cpu: 864 MHz 4 core, sistem ope
lei478.35
Wireless Access Point Mikrotik C52IG-5HAXD2HAXD-TC, hAP aX2 AX1800, WI- FI6, Standarde wireless: Cpu: 864 MHz 4 core, sistem operare: RouterOS (v7 only), 1 GB ram, memorie 128Mb NAND, Dual band: 5Ghz 802.11a/n/ac/ax, 2.4Ghz 802.11b/g/n/ax, data rate: 5 G
NAS QNAP 262 3-Bay, CPU Intel Celeron N5105/N5095 4-core/4-thread Processor, RAM 8 GB (onboard, not expandable), HDD 3.5" SATA 6
lei3,033.72
NAS QNAP 262 3-Bay, CPU Intel Celeron N5105/N5095 4-core/4-thread Processor, RAM 8 GB (onboard, not expandable), HDD 3.5" SATA 6Gb/s (support 2.5" via optional TRAY-25-NK-BLK03) (neincluse), LAN: 1 x 2.5GbE, USB3.2 Gen2: 2 USB3.2 Gen1: 1, tower,
MIKROTIK, CSS610-8P-2S+IN, 8P, 2 SFP+ Port , Indoor Switch, SwitchOS Lite, 64 KB Flash, interfata: 8 x 10/100/1000 POE, 2 x SFP+
lei1,048.98
MIKROTIK, CSS610-8P-2S+IN, 8P, 2 SFP+ Port , Indoor Switch, SwitchOS Lite, 64 KB Flash, interfata: 8 x 10/100/1000 POE, 2 x SFP+ ports, Dimensiuni: 272x208x44mm.
SWITCH HU CE6863E-48S6CQ (48*25GE SFP28, 6*100GE QSFP28, 2*AC power modules, 4*fan modules, port-side intake)
lei16,460.15
SWITCH HU CE6863E-48S6CQ (48*25GE SFP28, 6*100GE QSFP28, 2*AC power modules, 4*fan modules, port-side intake)
Huawei Switch CE6881-48T6CQ-B switch(48*10GE RJ45,6*100GE QSFP28,2*AC power modules) - 02353GLC-004
lei16,786.34
Huawei Switch CE6881-48T6CQ-B switch(48*10GE RJ45,6*100GE QSFP28,2*AC power modules) - 02353GLC-004
SW HUAWEI CE6881-48S6CQ-B switch (48*10G SFP+, 6*100G QSFP28, 2*AC power modules, 4*fan modules, port-side intake)
lei12,632.33
SW HUAWEI CE6881-48S6CQ-B switch (48*10G SFP+, 6*100G QSFP28, 2*AC power modules, 4*fan modules, port-side intake)
Miktrotik HAP AC1200 DUAL BAND WIRELESS ROUTER, 5 PORTURI 10/100/1000mbps, 1 x POE, 1 x USB, 2.4Ghz-300 Mbps, 5Ghz-867Mbps, 2 a
lei527.14
Miktrotik HAP AC1200 DUAL BAND WIRELESS ROUTER, 5 PORTURI 10/100/1000mbps, 1 x POE, 1 x USB, 2.4Ghz-300 Mbps, 5Ghz-867Mbps, 2 antene externe, 256Mb RAM, quad-core CPU 716 MHz, Wi-Fi 5.
SWITCH MIKROTIK CRS504-4XQ-IN, 1 x 10/100Mbps, 4 x 100 QSFP28 , Procesor: 650 MHz, 64MB RAM, 16MB flash, dimensiuni: 320 x 185 x
lei3,276.97
SWITCH MIKROTIK CRS504-4XQ-IN, 1 x 10/100Mbps, 4 x 100 QSFP28 , Procesor: 650 MHz, 64MB RAM, 16MB flash, dimensiuni: 320 x 185 x 44 mm, racier: 2 vantilatoare.IP 20.
SWITCH HUAWEI S5735-L48P4X-A1 48P GB, 4P 10GB SFP+, POE+ RACKABIL, L2+ MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series Bas
lei2,452.32
SWITCH HUAWEI S5735-L48P4X-A1 48P GB, 4P 10GB SFP+, POE+ RACKABIL, L2+ MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series BasicSW, PerDevice
SWITCH HUAWEI S5735-L48T4X-A1 48P GB, 4P 10GB SFP+, RACKABIL, L2+ MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series BasicSW,
lei1,801.25
SWITCH HUAWEI S5735-L48T4X-A1 48P GB, 4P 10GB SFP+, RACKABIL, L2+ MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series BasicSW, PerDevice
SWITCH HUAWEI S5735-L24P4S-A1 24P GB, 4P SFP, POE+, RACKABIL, L2+ MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series BasicSW,
lei1,104.33
SWITCH HUAWEI S5735-L24P4S-A1 24P GB, 4P SFP, POE+, RACKABIL, L2+ MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series BasicSW, PerDevice
SWITCH HUAWEI S5735-L24T4S-A1 24PGB - include si LICENTA HUAWEI S57XX-L Series BasicSW, PerDevice
lei518.76
SWITCH HUAWEI S5735-L24T4S-A1 24PGB - include si LICENTA HUAWEI S57XX-L Series BasicSW, PerDevice
SWITCH HUAWEI S5735-L24T4X-A1 24P GB, 4P 10GB SFP+, RACKABIL, L2+ MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series BasicSW,
lei1,185.55
SWITCH HUAWEI S5735-L24T4X-A1 24P GB, 4P 10GB SFP+, RACKABIL, L2+ MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series BasicSW, PerDevice
SWITCH HUAWEI S5735-L8T4S-A1 8P GB, 4SFP, RACKABIL, L2 MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series BasicSW, PerDevice
lei462.43
SWITCH HUAWEI S5735-L8T4S-A1 8P GB, 4SFP, RACKABIL, L2 MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series BasicSW, PerDevice
WIRELESS ACCESS POINT HUAWEI AIRENGINE 5761R-11E, 802.11ax OUTDOOR, 2+ 2/2 DOUA BENZI, ANTENA EXTERNA, DUAL RADIO, WIFI6, USB, 1
lei1,066.34
WIRELESS ACCESS POINT HUAWEI AIRENGINE 5761R-11E, 802.11ax OUTDOOR, 2+ 2/2 DOUA BENZI, ANTENA EXTERNA, DUAL RADIO, WIFI6, USB, 1GB - include si PROTECTIE LA DESCARCARE ELECTRICA HUAWEI POWER LIGHTNING ARRESTER 20KA 1.8KV 220V; MODULATOR DE SEMNAL SIGNAL A
WIRELESS ACCESS POINT HUAWEI AIRENGINE 5761R-11
lei1,066.34
WIRELESS ACCESS POINT HUAWEI AIRENGINE 5761R-11, 2P GB, SFP, 802.11ax, 2 +2 DUAL BANDS, DIRECTIONAL ANTENA, MANAGED, WIFI6 - include si PROTECTIE LA DESCARCARE ELECTRICA HUAWEI POWER LIGHTNING ARRESTER 20KA 1.8KV 220V; MODULATOR DE SEMNAL SIGNAL ARRESTER
NAS QNAP 453E 4-Bay, CPU Intel Celeron J6412 4-core/4-thread processor, burst max. 2.6 GHz, RAM 8 GB DDR4 onboard not expandable
lei3,439.50
NAS QNAP 453E 4-Bay, CPU Intel® Celeron® J6412 4-core/4-thread processor, burst up to 2.6 GHz, RAM 8 GB DDR4 onboard not expandable, HDD 2.5" & 3.5" SATA 6Gb/s, 3Gb/s (neincluse), LAN: 2 x 2.5GbE, USB3.2 Gen2: 2 USB2.0: 2, tower, adaptor al
NAS QNAP 253E 2-Bay, CPU Intel Celeron J6412 4-core/4-thread processor, burst max. 2.6 GHz, RAM 8 GB DDR4 onboard not expandable
lei2,735.75
NAS QNAP 253E 2-Bay, CPU Intel® Celeron® J6412 4-core/4-thread processor, burst up to 2.6 GHz, RAM 8 GB DDR4 onboard not expandable, HDD 2.5" & 3.5" SATA 6Gb/s, 3Gb/s (neincluse), LAN: 2 x 2.5GbE, USB3.2 Gen2: 2 USB2.0: 2, tower, adaptor al
WIRELESS ACCESS POINT HUAWEI AIRENGINE 5761-11, 1P GB, 802.11ax INDOOR, 2+2 DOUA BENZI, SMART ANTENA, DUAL RADIO, WIFI6, USB, RJ
lei262.00
WIRELESS ACCESS POINT HUAWEI AIRENGINE 5761-21, 1P GB, 802.11ax INDOOR, 2+2 DOUA BENZI, SMART ANTENA, DUAL RADIO, WIFI6, USB, RJ45
NAS QNAP 432PXU-RP 4-Bay, CPU Annapurna Labs Alpine AL324 1.7GHz Quad Core, RAM 2GB DDR4 UDIMM (max. 16GB), 2.5/3.5 SATA 6Gbps H
lei4,476.19
NAS QNAP 432PXU-RP 4-Bay, CPU Annapurna Labs Alpine AL324 1.7GHz Quad Core, RAM 2GB DDR4 UDIMM (max. 16GB), 2.5/3.5 SATA 6Gbps HDD ( neincluse), LAN: 2 x 10GbE SFP+ + 2 x 2.5GbE, USB3.0: 4, 1U, redundant PSU, garantie 3 ani
MikroTik RouterBOARD 4011iGS+5HacQ2HnD with Annapurna Alpine AL21400Cortex A15 CPU (4-cores, 1.4GHz per core), 1GB RAM, 512 MB,
lei1,325.07
MikroTik RouterBOARD 4011iGS+5HacQ2HnD with Annapurna Alpine AL21400Cortex A15 CPU (4-cores, 1.4GHz per core), 1GB RAM, 512 MB, 10xG bit LAN,1xSFP+ port, built-in 5Ghz 802.11ac four chain wireless with exter
MikroTik RouterBOARD 4011iGS+ with Annapurna Alpine AL21400 Cortex A15CPU (4-cores, 1.4GHz per core), 1GB RAM, 512 MB, 10xGbit L
lei1,000.51
MikroTik RouterBOARD 4011iGS+ with Annapurna Alpine AL21400 Cortex A15CPU (4-cores, 1.4GHz per core), 1GB RAM, 512 MB, 10xGbit LAN, 1xSFP+port, RouterOS L5, desktop case, rackmount ears, PSU
NAS QNAP 464eU 4-Bay, CPU Intel Celeron N5105/N5095 4-core/4-thread processor (burst max. 2.9 GHz), RAM: 8GB DDR4 (not expandabl
lei4,603.65
NAS QNAP 464eU 4-Bay, CPU Intel Celeron N5105/N5095 4-core/4-thread processor (burst max. 2.9 GHz), RAM: 8GB DDR4 (not expandable), HDD: 2.5"/3.5" SATA 6Gbps (neincluse), LAN: 2 x 2.5GbE (2.5G/1G/100M/10M), 2 x M.2 2280 PCIe, USB3.2 Gen2: 2 x Ty
Mikrotik CRS305-1G-4S+OUT FIBERBOX PLUS, Procesor: 800 MHz dual core, Sistem operare: RouterOS v7 / SwOS, 256Mb RAM, 16MB Flash,
lei917.52
Mikrotik CRS305-1G-4S+OUT FIBERBOX PLUS, Procesor: 800 MHz dual core, Sistem operare: RouterOS v7 / SwOS, 256Mb RAM, 16MB Flash, POE in 802.3af/at 42-57 V, interfata: 1 x 10/100/1000, 4 x SFP, Wwatherproof: IP66.
Wireless Access Point Mikrotik C52IG-5HAXD2HAXD-TC, hAP aX2 AX1800, WI- FI6, Standarde wireless: Cpu: 864 MHz 4 core, sistem ope
lei478.35
Wireless Access Point Mikrotik C52IG-5HAXD2HAXD-TC, hAP aX2 AX1800, WI- FI6, Standarde wireless: Cpu: 864 MHz 4 core, sistem operare: RouterOS (v7 only), 1 GB ram, memorie 128Mb NAND, Dual band: 5Ghz 802.11a/n/ac/ax, 2.4Ghz 802.11b/g/n/ax, data rate: 5 G
NAS QNAP 262 3-Bay, CPU Intel Celeron N5105/N5095 4-core/4-thread Processor, RAM 8 GB (onboard, not expandable), HDD 3.5" SATA 6
lei3,033.72
NAS QNAP 262 3-Bay, CPU Intel Celeron N5105/N5095 4-core/4-thread Processor, RAM 8 GB (onboard, not expandable), HDD 3.5" SATA 6Gb/s (support 2.5" via optional TRAY-25-NK-BLK03) (neincluse), LAN: 1 x 2.5GbE, USB3.2 Gen2: 2 USB3.2 Gen1: 1, tower,
MIKROTIK, CSS610-8P-2S+IN, 8P, 2 SFP+ Port , Indoor Switch, SwitchOS Lite, 64 KB Flash, interfata: 8 x 10/100/1000 POE, 2 x SFP+
lei1,048.98
MIKROTIK, CSS610-8P-2S+IN, 8P, 2 SFP+ Port , Indoor Switch, SwitchOS Lite, 64 KB Flash, interfata: 8 x 10/100/1000 POE, 2 x SFP+ ports, Dimensiuni: 272x208x44mm.
SWITCH HU CE6863E-48S6CQ (48*25GE SFP28, 6*100GE QSFP28, 2*AC power modules, 4*fan modules, port-side intake)
lei16,460.15
SWITCH HU CE6863E-48S6CQ (48*25GE SFP28, 6*100GE QSFP28, 2*AC power modules, 4*fan modules, port-side intake)
Huawei Switch CE6881-48T6CQ-B switch(48*10GE RJ45,6*100GE QSFP28,2*AC power modules) - 02353GLC-004
lei16,786.34
Huawei Switch CE6881-48T6CQ-B switch(48*10GE RJ45,6*100GE QSFP28,2*AC power modules) - 02353GLC-004
SW HUAWEI CE6881-48S6CQ-B switch (48*10G SFP+, 6*100G QSFP28, 2*AC power modules, 4*fan modules, port-side intake)
lei12,632.33
SW HUAWEI CE6881-48S6CQ-B switch (48*10G SFP+, 6*100G QSFP28, 2*AC power modules, 4*fan modules, port-side intake)
Miktrotik HAP AC1200 DUAL BAND WIRELESS ROUTER, 5 PORTURI 10/100/1000mbps, 1 x POE, 1 x USB, 2.4Ghz-300 Mbps, 5Ghz-867Mbps, 2 a
lei527.14
Miktrotik HAP AC1200 DUAL BAND WIRELESS ROUTER, 5 PORTURI 10/100/1000mbps, 1 x POE, 1 x USB, 2.4Ghz-300 Mbps, 5Ghz-867Mbps, 2 antene externe, 256Mb RAM, quad-core CPU 716 MHz, Wi-Fi 5.
SWITCH MIKROTIK CRS504-4XQ-IN, 1 x 10/100Mbps, 4 x 100 QSFP28 , Procesor: 650 MHz, 64MB RAM, 16MB flash, dimensiuni: 320 x 185 x
lei3,276.97
SWITCH MIKROTIK CRS504-4XQ-IN, 1 x 10/100Mbps, 4 x 100 QSFP28 , Procesor: 650 MHz, 64MB RAM, 16MB flash, dimensiuni: 320 x 185 x 44 mm, racier: 2 vantilatoare.IP 20.
SWITCH HUAWEI S5735-L48P4X-A1 48P GB, 4P 10GB SFP+, POE+ RACKABIL, L2+ MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series Bas
lei2,452.32
SWITCH HUAWEI S5735-L48P4X-A1 48P GB, 4P 10GB SFP+, POE+ RACKABIL, L2+ MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series BasicSW, PerDevice
SWITCH HUAWEI S5735-L48T4X-A1 48P GB, 4P 10GB SFP+, RACKABIL, L2+ MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series BasicSW,
lei1,801.25
SWITCH HUAWEI S5735-L48T4X-A1 48P GB, 4P 10GB SFP+, RACKABIL, L2+ MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series BasicSW, PerDevice
SWITCH HUAWEI S5735-L24P4S-A1 24P GB, 4P SFP, POE+, RACKABIL, L2+ MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series BasicSW,
lei1,104.33
SWITCH HUAWEI S5735-L24P4S-A1 24P GB, 4P SFP, POE+, RACKABIL, L2+ MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series BasicSW, PerDevice
SWITCH HUAWEI S5735-L24T4S-A1 24PGB - include si LICENTA HUAWEI S57XX-L Series BasicSW, PerDevice
lei518.76
SWITCH HUAWEI S5735-L24T4S-A1 24PGB - include si LICENTA HUAWEI S57XX-L Series BasicSW, PerDevice
SWITCH HUAWEI S5735-L24T4X-A1 24P GB, 4P 10GB SFP+, RACKABIL, L2+ MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series BasicSW,
lei1,185.55
SWITCH HUAWEI S5735-L24T4X-A1 24P GB, 4P 10GB SFP+, RACKABIL, L2+ MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series BasicSW, PerDevice
SWITCH HUAWEI S5735-L8T4S-A1 8P GB, 4SFP, RACKABIL, L2 MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series BasicSW, PerDevice
lei462.43
SWITCH HUAWEI S5735-L8T4S-A1 8P GB, 4SFP, RACKABIL, L2 MANAGEMENT - include si LICENTA HUAWEI S57XX-L Series BasicSW, PerDevice
WIRELESS ACCESS POINT HUAWEI AIRENGINE 5761R-11E, 802.11ax OUTDOOR, 2+ 2/2 DOUA BENZI, ANTENA EXTERNA, DUAL RADIO, WIFI6, USB, 1
lei1,066.34
WIRELESS ACCESS POINT HUAWEI AIRENGINE 5761R-11E, 802.11ax OUTDOOR, 2+ 2/2 DOUA BENZI, ANTENA EXTERNA, DUAL RADIO, WIFI6, USB, 1GB - include si PROTECTIE LA DESCARCARE ELECTRICA HUAWEI POWER LIGHTNING ARRESTER 20KA 1.8KV 220V; MODULATOR DE SEMNAL SIGNAL A
WIRELESS ACCESS POINT HUAWEI AIRENGINE 5761R-11
lei1,066.34
WIRELESS ACCESS POINT HUAWEI AIRENGINE 5761R-11, 2P GB, SFP, 802.11ax, 2 +2 DUAL BANDS, DIRECTIONAL ANTENA, MANAGED, WIFI6 - include si PROTECTIE LA DESCARCARE ELECTRICA HUAWEI POWER LIGHTNING ARRESTER 20KA 1.8KV 220V; MODULATOR DE SEMNAL SIGNAL ARRESTER
NAS QNAP 453E 4-Bay, CPU Intel Celeron J6412 4-core/4-thread processor, burst max. 2.6 GHz, RAM 8 GB DDR4 onboard not expandable
lei3,439.50
NAS QNAP 453E 4-Bay, CPU Intel® Celeron® J6412 4-core/4-thread processor, burst up to 2.6 GHz, RAM 8 GB DDR4 onboard not expandable, HDD 2.5" & 3.5" SATA 6Gb/s, 3Gb/s (neincluse), LAN: 2 x 2.5GbE, USB3.2 Gen2: 2 USB2.0: 2, tower, adaptor al
NAS QNAP 253E 2-Bay, CPU Intel Celeron J6412 4-core/4-thread processor, burst max. 2.6 GHz, RAM 8 GB DDR4 onboard not expandable
lei2,735.75
NAS QNAP 253E 2-Bay, CPU Intel® Celeron® J6412 4-core/4-thread processor, burst up to 2.6 GHz, RAM 8 GB DDR4 onboard not expandable, HDD 2.5" & 3.5" SATA 6Gb/s, 3Gb/s (neincluse), LAN: 2 x 2.5GbE, USB3.2 Gen2: 2 USB2.0: 2, tower, adaptor al
WIRELESS ACCESS POINT HUAWEI AIRENGINE 5761-11, 1P GB, 802.11ax INDOOR, 2+2 DOUA BENZI, SMART ANTENA, DUAL RADIO, WIFI6, USB, RJ
lei262.00
WIRELESS ACCESS POINT HUAWEI AIRENGINE 5761-21, 1P GB, 802.11ax INDOOR, 2+2 DOUA BENZI, SMART ANTENA, DUAL RADIO, WIFI6, USB, RJ45
NAS QNAP 432PXU-RP 4-Bay, CPU Annapurna Labs Alpine AL324 1.7GHz Quad Core, RAM 2GB DDR4 UDIMM (max. 16GB), 2.5/3.5 SATA 6Gbps H
lei4,476.19
NAS QNAP 432PXU-RP 4-Bay, CPU Annapurna Labs Alpine AL324 1.7GHz Quad Core, RAM 2GB DDR4 UDIMM (max. 16GB), 2.5/3.5 SATA 6Gbps HDD ( neincluse), LAN: 2 x 10GbE SFP+ + 2 x 2.5GbE, USB3.0: 4, 1U, redundant PSU, garantie 3 ani
MikroTik RouterBOARD 4011iGS+5HacQ2HnD with Annapurna Alpine AL21400Cortex A15 CPU (4-cores, 1.4GHz per core), 1GB RAM, 512 MB,
lei1,325.07
MikroTik RouterBOARD 4011iGS+5HacQ2HnD with Annapurna Alpine AL21400Cortex A15 CPU (4-cores, 1.4GHz per core), 1GB RAM, 512 MB, 10xG bit LAN,1xSFP+ port, built-in 5Ghz 802.11ac four chain wireless with exter
MikroTik RouterBOARD 4011iGS+ with Annapurna Alpine AL21400 Cortex A15CPU (4-cores, 1.4GHz per core), 1GB RAM, 512 MB, 10xGbit L
lei1,000.51
MikroTik RouterBOARD 4011iGS+ with Annapurna Alpine AL21400 Cortex A15CPU (4-cores, 1.4GHz per core), 1GB RAM, 512 MB, 10xGbit LAN, 1xSFP+port, RouterOS L5, desktop case, rackmount ears, PSU