Designed for experimental PA-18 aircraft and direct copies with a max gross weight of 2000 lbs, the heavy duty T3 offers 1500 lbs/in compression for shock absorption that's neither abrupt nor too yielding. The coil over shock is calibrated to provide impact cushioning and limited rebound. If you typically run at or just beyond gross and/or frequently fly in rough backcountry conditions, we recommend upgrading to the double shock T3.