This is Kodiak Slip On 13" 7,000lb Capacity Disc Brake Kit that features both Stainless Steel components and dacromet components. This kit is includes Galvanized 8 Lug Idler hubs with Bearings, that install on your trailers spindle. The rotor is then secured in place when the wheel is mounted and the lug nuts are tightened. All Kodiak rotors feature the vented design to dissipate heat and yield a low towing temperature. This particular combination utilizes Kodiaks Stainless Steel Calipers, proven to be the best trailer disc brake caliper on the market. The stainless steel calipers also have a stainless steel piston, stainless steel bolt bushings, brass fittings, and stainless steel backed brake pads.