Max-Air™ Load Adjusting Rear Shock Absorbers (MA830) by Monroe®. If you use your vehicle for towing trailers or carrying heavy loads, these shocks are what you need as they are engineered to maintain the ride height of the vehicle even when up to 1100 lbs. of additional weight is loaded. Monroe Max-Air Rear Air Adjustable Shocks can be inflated to 150 psi with the vehicle loaded and deflated for normal driving.