Wide Compatibility: This Stack Adapter Kit for two post lifts, bridge jacks, inground car and truck lifts; Fits for Challenger lifts that have the round drop-in pad assembly Such as model CL9, CL10 X10 SA10CL10 VS10, E10, SA10x EV1020, CS1020WV and AV1020WV. Replaces Challenger part # 10315，Used on many Challenger lifts under 15K with drop-in style arms Function: This adapter kit provides the necessary height extensions to safely and efficiently lift vehicles with challenging pick-up points on vehicles with running boards or side steps. By stacking and combining them, you can achieve height increases of 3/ 6/ 9 inches Heavy Duty Steel: Crafted from high-strength #45 steel, this adapter is built for extreme durability. It undergoes specialized treatment for superior corrosion resistance and a robust 12,000 lbs load capacity, ensuring long-term, reliable performance under high-stress conditions Easy to Install: Features a plug-and-play design. Simply take out the screw pad, drop in the stack adapter extension and replace screw pad to reach lifting points. this design allows you to quickly install and remove the stack adapter Stack Adapter Extension Kit includes: 4 pieces 3-inch Stack Extensions, 2 pieces 6-inch Stack Extensions & 2 pieces Organizer Racks with hardware. Organizer racks mount to automotive lift column to keep adapters within reach. (Note: The pin diameter of the adapter is 2-3/8" 60mm 2.36" ;Not work for Older lifts adapter with 2-1/8" 54mm 2.13" holes) Challenger Stack Truck Adapter Kit Four 3" & Two 6" Stack Adapter Kit fit for 10,000 and 12,000 lb. two post automotive lifts. Drop-in style stack adapters help reach pickup points on vehicles with running boards or side steps. Simply take out the screw pad, drop in the stack adapter extension and replace screw pad to reach lifting points. Stack Adapter Extension Kit includes four 3″ Stack Extensions, two 6″ Stack Extensions & two Organizer Racks with hardware. Organizer racks mount to automotive lift column to keep adapters within reach. Works with all Challenger two post automotive lifts.