I know they use Skyjacker and Superlift for some of them, not sure of the special. However, these kits are cheap becaue they come with rear blocks and no steering correction or brake line correction. Once you add up the price for rear springs, steering drop, and brake lines, you will be in the same price range as a reputable company such as Tuff Country's EZ ride. Many people here run this brand, including myself and I love it. Do yourself a favor and get rear springs instead of blocks.