That’s an Aviation Fabricators seat. As I understand it, in order to legally install it, AvFab requires you send the seat to them first to be refurbished and then they issue a new STC for your aircraft’s serial number. You can’t transfer the old STC from one airplane to another.
The real kicker is they charge just as much to refurbish a used seat as they do to sell you a new one.

Maybe there policy has changed. I don’t see it on their website anymore:
https://avfab.com/products/view/cessna-150-152-child-seat-auxillary/On the plus side, their seat fits any model 150/152.