DSLRKIT Gigabit 48V 30watt PoE Injector Adapter Power Over Ethernet 802.3at af UBNT AP 1000Mbps

Raspberry Pi 3B+ can work with this poe injector after installed this PoE hat or micro USB PoE Splitter
This injector lets you power 802.3af compatible devices, with no additional adapter needed. Just plug the network cable(not included) into your network switch and into the "Data In" port, then plug the cable to your device into the "PoE" port with your existing network cable
This Adapter support 10/100/1000Mbps gigabit ethernet connection, RJ45 PoE port using 4,5,7,8 pin as power transfer, Please do not connect any device that does not support the "PoE" port, this will damage your device
This is an 802.3af compatible device, but it does NOT include the 802.3af/802.3at compliant detection feature. It supplies power NO MATTER WHAT, so don't plug the "PoE" side into anything that isn't ready for it