We have 2 shell buckles vintage nos items.   They are both the same style, slightly different in size, the more ornate one on the bottom of the first photo is about 1 1/2" x 1 3/8" and the other one is about 1 1/4" x 1 1/8".  The back will acommadate a belt about 1" wide.  They have been stored together therefore the center black portions of both of them have a bit of white wear showing on the center squares. 

2 Shell Buckles Vintage nos