Size 9, not resizable. Front is 5/8" tall at widest point. Some damage and glue repair at back of shank where it was once split. Made from black celluloid or another early plastic with a tiny photo portrait under translucent plastic. These rings are tied to a specific USA folk-art tradition of prison-made jewelry. Inmates had limited access to precious metals, but cheap early plastic could be scavenged from everyday objects, particularly toothbrush handles and pen parts. They could be melted, remolded, filed and polished. It's a homemade love token. Then in the 1930s and 40s the art form flourished when photo jewelry and "sweetheart" objects were deeply embedded in American pop culture. I doubt this was prison-made - it's probably WW2 era. I'm guessing that from her hairstyle!