The Tow Zone Stainless Steel G5 Trailer Disc Brakes have a large single piston design, ceramic pads, and stainless steel backing plates with venting holes. Their all aluminum calipers shed heat 5x faster than cast iron calipers. Feature slim design, bi-metal piston, 50% thicker rubber boot for positive and faster piston withdrawal, rotating swivel connector, oil impregnated bronze bushings, one-piece stainless steel bleeder valve with teflon coating, and a square o-ring with a slant edge. Stainless steel parts will not rust or corrode. GalvX hub finish. 5-Lug Trailer Disc Brake replaces 10" Drum Brake. Lifetime warranty.