We offer this Stainless Steel bolt for the Specific purpose of mounting your Caliper Bracket to your trailers Brake Flange on the standard 4 Hole flange on 3,500lb trailer axles. You would need (4) of these bolts per flange. This bolt accommodates Kodiaks 3,500lb Caliper Mounting Brackets. This listing is for (1) Bolt and also includes (2) Stainless Steel Washers, (1) Stainless Steel Lock Washer, and (1) Stainless Steel Hex Nut