When conditions turn muddy, sandy, wet, or if riders just want a long lasting racing chain, RK offers a sealed supercross, motocross and off-road racing chain called MXU. RK's GB520MXU features ultra-thin UW-seals which is perfect for bikes with narrow clearance and delivers triple the life expectancy when compared to a non-sealed chain. RK's UW-Ring seals utilize triple barrier grease protection plus anti-debris technology. Anti-debris protection is vitally important to maximize chain wear life by eliminating debris friction between internal components. RK's UW seals also feature small contact points to reduce cold start drag.