Dexter Left Hand Single-Servo 10" x 2-1/4" Hydraulic complete brake assembly. Single plunger comes from the wheel cylinder (Most Common Style) 3,500lb capacity per pair. Mounts with 4 bolts (included), bolts are 2-7/8" apart, center to center. Uses 10" Hub/Drums. Nuts-6-17 and washers-5-8 sold separately. Fits standard 3500lb axle with a 4 bolt pattern on the mounting flange. Left Hand(driver's side) Complete assembly ready to bolt on and connect line For use with a 10" inside diameter drum The shoes are 2 1/4" wide To determine the size of the brake, you need 2 measurements. The first is the diameter of the brake(D). The second is the width of the shoe(W). It is good to take note of how many mounting bolts the brake has.