Beautiful!  10k GOLD FILLED POCKET/PENDANT/BUTTON WATCH.

Pendant type as it has a loop at the top and bottom as well.

Case marked:  3/0s, B&B, 20 Years, and 6510487.

Movement marked: Elgin, Elgin USA, and 27494481.

From what I found online this is a Model 3, made in 1925, 3/0s, grade 463,, 7j and nickel finish movement.  The case is gold filled...most likely 10k.

Condition:  The watch winds and the time can be changed.  No scratches on case....light signs of age only.  Doesnt run...may need oiled or light maintenance.  No glass.  Still has both the top and bottom loops.

It will be protected well and insured.

Location E1, FBMP, MER