These springs are made for use on the super short big bore dampers (Item 42305) that debuted on the TRF419X. The set includes 3 different stiffnesss, which you can use to swiftly alter your setup. Short Spring (Soft) x2 Short Spring (Medium) x2 Short Spring (Hard) x2 Marking sleeves for hard (yellow) and soft (red) x2 each Free length: 20mm Compatible with super short big bore dampers.