Industrial power supply; Compatible with 4U 19 Rackmount TI-R4U (sold separately) Provides up to 1000W of power (48V DC, 21A); High efficiency 94% and low power dissipation Built-in active Power Factor Controller; Forced air cooling via built-in DC fans Protections: Short circuit, overload, over voltage, over temperature; UL 508 approved; Built-in DC OK relay contact 100% full load burn-in test; -25° 70° C (-13° 158° F) operating temperature range