FRM220 CH02NMC DC two slot fiber chassis with embedded neg. DC power 18 72V input construction_single fiber A patented removable flashlight improves A patented removable flashlight improves visibility while navigating through a congested enclosure High Quality This product is optional and intended for high end applications requesting a single package unit (embedded power supply) and no separate power adapter and is especially intended for telecom grade environment weher DC48V is the only available power there are also the FRM220 CH02NMC AC (single AC 90 240V power supply) and FRM220 CH02NMC AD chassis (dual redundant AC and DC 18~72V power supplies)