I needed to power some cameras using Power over Ethernet but they only supported 12V input, so I ordered some PoE extractors from ali. Here they are for your information.

Black one

White waterproof one

Conclusion

They both only support 100Mbps over 2 pairs. The wateproofing was quite annoying to remove but not impossible. It seems they both can be modified to support different input/output voltage. As you can see in the pictures, they are both using H6225K step-down regulator in a very similar design.

The circuit mostly corresponds to following schematic found on the internet:

Thank you for your attention.