Shimano RD-RX820 GG Adjustment Gauge (12 Speed)

Shimano RD-RX820 GG Adjustment Gauge Description: Don't just guess, use the GG Adjustment Gauge to properly set the correct gap between the upper pulley guide wheel and the cassette for flawless shifting. Designed to work with 12-speed Shimano gravel and road rear derailleurs. The round cut-out is perfect for hanging on the home shop peg board, so you know exactly where you left it. Features: Aids is setting the proper distance of the upper guide wheel to the cassette Experience shifting the way Shimano engineers intended For use with road and gravel 12-speed rear derailleurs Compatible with the following Shimano rear derailleurs: RD-R7100 RD-R7150 RX-820