AXIS F9104-B is a 4-channel Barebone main unit part of the 2nd generation F-series. AXIS F9104-B has no casing. It is UL recognised and is meant to be integrated into a something else (ex: machine...). The final product has to be UL certified. Up to 4x F21, F7225-RE or F4105-LRE video sensors can be connected to it. it has a 10-48V DC and an Ethernet port. AXIS F9104-B is PoE Class 4. Max 25,5W. AXIS TU6001 Connector 3-in (for DC power) has to be purchased separately. AXIS F9104-B main unit is NOT compatible with the 1st generation of F-series sensors (F1005-E, F1015-E, F1025-E, F1025 F4005, F4005-E).