Designed to handle the demands of high mileage and severe use class 6-8 trucks and buses Nitrogen gas charge maintains tire to road contact for improved ride and handling by reducing aeration and shock fade Robust hydraulic lock out prevents over extension of air bags top out of the piston and averts damage to seal assembly most applications 10 Stage valving tuned specifically to each vehicle adjusts to road extremes while larger 1-3/4 in. bore provides more efficient damping control to provide consistency and a smooth ride most applications All weather fluid contains special additives to assist with extreme temperatures and help reduce oil breakdown while larger 2-3/8 in. reserve tube holds more fluid to improve performance most applications