This is a must buy for use with any springs where the factory spring perches don't have proper rubber insulation to prevent metal-on-metal contact. I use these on every lowering spring I've ever installed on Datsun Z cars and highly recommend them to reduce powdercoat or paint failure on the spring perches. If you use lowering springs and they don't compress slightly upon installation, these silencers will help to eliminate the clanking noise when going over large bumps.