M-series rear derailleurs are designed to work with 7, 8, and 9-speed Shimano-compatible mountain and road shifters. Marvo LT rear derailleurs are built with precision rigid aluminum construction. Let these miracle workers get any bike rolling again. - Lightweight aluminum construction - Steel pulley cage for extra chain-rub durability - Compatible with Shimano 7, 8, and 9-speed mountain and road systems