Cognito 11-25 Chevy/GMC Silverado/Sierra 2500/3500 HD 2WD/4WD Deaver Mini Leaf Pack SetThe stock bottom overload spring is very harsh in spring rate, this mini pack is a progressive overload that will ride better and provide 1 2. 5 inches of rear lift if one or both of the spacer blocks are removed. Get better ride quality and the added height with one product. These mini packs are only compatible with the stock spring packs, and they fasten to the stock spring packs with a new center pins (included). This Part Fits: Year Make Model