The Cage Guard is designed to add a layer of protection to your derailleur pulley cage to help prevent costly damage caused by rocks and debris. By limiting impact damage, the Cage Guard helps maintain smooth shifting performance and keeps your high-end derailleur in top condition.Precision-machined in MRPs Colorado factory, the Cage Guard is made from durable, low-friction Delrin thermoplastic, designed to withstand normal impacts and glide over rocks. SRAM T-Type derailleurs are known for their strength, but their low-hanging pulley cages are highly susceptible to rock strikes. The metal cages on GX, XO, and XX models can snag, leading to damage and misalignment. The carbon fibre outer cages on XXSL derailleurs are even more vulnerable to impact, risking delamination or failure.