Brand: 1969 GAP Jeans. This GAP line was launched in 1999 and the belt likely dates from 1999-2006.

Pinned in photos to fit X-Small mannequin. Marked a size Medium, but I would call this a Large or X-Large, unless it's to be worn slung low or used to cinch a coat.

Measures: 3" wide. When buckled, diameter measures 32"-36".