SRAM Dual Drive Click Box 3 Speed ConnectorSRAM Dual Drive Click Box 3 Speed Connector SRAM's Dual Drive is a unique drivetrain that combines a three speed internal gear hub with an external cassette and derailleur. The result is a wide range of gears in a clean, one handed control system. SRAM's Dual Drive Click box attaches to the Dual Drive huband the Dual Drive shifter via cableso you can shift between the hub's three internal gears. For use with Dual Drive 3 speed shifter Made of plastic