SuperSprings SSR-111-54 SumoSprings Solo Rear Bump Stop Upgrade Kit Replaces original rear bump stops to stabilize sway, improve overall driver control and add comfort Provides progressive load control and compresses up to 80% of original height with full memory rebound "Airless airbag" design means no air leaks, air line or compressors Proprietary material provides softer engagement for enhanced comfort Built tough in the USA