This is a over Ethernet (PoE) expansion board for 3B+/4B that supports the IEEE 802.3af network standard. If you already have a PoE router or switch that supports the IEEE 802.3af network standard, with this expansion board, you can connect the to the network and supply with just one network cable. Suitable for 3B+/4B, can be used together with shell, does not take up more space Support PoE over Ethernet, support IEEE 802.3af PoE network standard Fully isolated switch mode supply (SMPS). Adopting a more compact component layout scheme, the overall volume is smaller and the use is more flexible PoE input: 37V ~57V DC input output: 5V 2.5A DC output Network Standard: Support IEEE 802.3af PoE Colour:blue Material:PCB Size:65 x 32MM Package Contents: 1 x Poe HAT Expansion Board Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.