Can you tell what this is?

Thanks for reaching out to us. This is the hinge's "shoe". We don't sell it separately, so you'd have to replace the whole hinge. We also recommend replacing the top and bottom hinges at the same time. Start by taking a look at the 36-048's specifications and see how they compare with your old part.

Note that we recommend reusing the old screws. If you need more, you can consult a local hardware store for them to match up.

Detail of 36-048

Additional dimensions for 36-048