This Sram X5 medium cage gear mech in Silver is suitable for use with Dahon gear systems 8/9sp (21/24/27sp) speed systems, using either Sram trigger or Sram Grip Shifter. This is also suitable for use with the Sram Dual Drive system, using either the 7/8/9sp Dual Drive Trigger shift or the single side dedicated dual drive 24/27sp shifters. Note: Colour is Silver