WHY CHOOSE YOUXMOTO TRAILER BRAKE KITS? (For trailer use only.) * Good dynamic balance; High fatigue strength. * Good stiffness and elasticity; High precision without runout. * High temperature resistant lithium ester. * electric brake assembly to provide safer and more stable parking. * Design from professional factory, Improved performance. SIZE: * Pair of 10" x 2.25" electric brake assemblies. * 4 Hole mounting, Rated up to 3,500 lbs to 4,000 lbs. * FITS For Dexter, For Al-Ko, For Lippert, For Hayes, For Rockwell, or For Quality trailer axles. Package: * 10 inch electromagnetic brake left hand*2+right hand*2 * Spring pad*16 * Nut*16 Warm tip: Youxmoto provides 8-hour fast response.