These springs are produced to be used regarding the super short big bore dampers (Item 42305) that debuted regarding the TRF419X. The set includes 3 different stiffnesss, that can be used to swiftly change your setup. Brief Spring (smooth) x2 Brief Spring (moderate) x2 Brief Spring (complex) x2 Marking sleeves for hard (yellow) and soft (red) x2 each Free length: 20mm appropriate for super quick big bore dampers.