Ring Doorbells have a delicate doorbell button that may crack or get lost after some time. The company does not sell replacement parts and insists on you purchasing a whole new unit as a replacement. That is where 3D printers come in to make a cheap replacement part cheap. This works and YMMV.

Ring makes several doorbell models (1, 2, 3, Pro etc.), so if yours looks like the one in the pic, then chances are that this button may actually fit. I think the one in the pic is a Gen 1.