Check the listing for details. 5-4.5" Bolt Circle 3,500 lbs. Trailer Axle Hydraulic Brake Kit. Condition: New. Listed at 269.99 USD. Pair of 10" hub/drum 5 studs 4.5" bolt circle (2 5/8" from center of one stud to the center of the next stud) using L68149 inner and L44649 outer bearing. Contains inner bearings, outer bearings, grease seals, grease caps, ultra lube grease caps, spindle washers, spindle nuts, cotter pins, tang washers, and lug nuts. (84 Spindle) Pair of 10" x 2.25" Dacromet Coated hydraulic trailer brake assemblies with parts. 4 Hole Mounting. For Alko, Dexter, Quality, or other popular trailer axle manufacturers. Only works on 3,500 lbs trailer axles with four hole brake flange. Includes mounting hardware. These are fully assembled backing plates with shoes, springs, and cylinders attached and ready to be mounted. The pair includes one left hand and one right hand brake assembly. Bolt Circle Guide will be included to verify the correct hub has been sent