PR2 High Volume Bladder cap fit 2003-18 KX85/100. Larger Nitrogen volume improves many aspects of the temperature and performance of the shock. MOST IMPORTANTLY, it eliminates the cheap exposed rubber plug that comes stock on the KX85/100 with the potential for slow leaks or failures. Often the stock OEM bladder has leaked and the customer has no knowledge of it because it has happened slowly and it often mistaken for a "worn out" rear shock. A must on newer KX85/100 that no longer have a filler valve.