This is a over Ethernet (PoE) expansion board for 3B+/4B supports the IEEE 802.3af network standard. If you already have a PoE router or switch supports the IEEE 802.3af network standard, with this expansion board, you can the to the network and supply with just one network cable. Suitable for 3B+/4B, can be used 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 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 the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.