This is a broad black strap with a brass ring at each end a brass buckle at the top.

There are four horse brasses suspended from it :

A horse head in a horseshoe which measures 4½" (11.3cm) x 3½" (9cm)

A pierced brass with a central clover leaf which measures 4¼" (11cm) x 3½" (9cm)

A brass with a central dome which measures 4¼" (11cm) x 3½" (9cm)

A pierced brass with a central heart which measures 4¼" (11cm) x 3½" (9cm)

Dimensions : Leather mount 22" (56cm) Total length 
Weight 1lb 5oz (557g)

Ref :  Martingale 4 brasses