The SRAM MRX 6 Speed Shifter is the original GripShift, ergonomically designed and massively popular thanks to its entry level price and compatibility with Shimano derailleurs. Features a 2:1 actuation ratio. The MRX Twist Shifters are Shimano Compatible and feature a 2:1 actuation ratio and SRS technology for light precise indexing. Whether your ride of choice includes gently rolling terrain or fast downhill descents, the MRX will follow you there with crisp.