Includes a polypropylene hold-down strap with positive locking quick-disconnect buckle, matched with a molded base and four No. 10 pan head mounting screws. BH24P: 11-1/4″L x 8-1/2″W* x 1-3/8″H, BH27P: 12-5/8″L x 8-1/2″W* x 1-3/8″H, BH31P:13″L x 7-3/8″W* x 1″H.