10in x 2-1/4in Left Hand electric complete brake assembly. 3,500lb capacity per pair. Mounts with 4 bolts (included), bolt holes are 2-7/8in apart, center to center. Uses 10in Hub/Drums. Nuts-6-17included Washers-5-8sold separately. These components have passed the CSA Standard CAN3-D313-M85 For Trailer Running Gear, a stringent standard mandated by the Government to assure brake effectiveness and structural integrity of the components.