It's new design makes it one of the lightest and slimmest heart rate monitors

Ideal internal rim width is 23mm

5-Digit Programmable Combination Lock

Weight (no hardware) – 20g

for enough breathability and support for long ride adventures

SHIMANO Rear Derailleur RD-M3100, Alivio ,SGS, 9-Speed, Top Normal wahoopromo It's new design makes itThe SHIMANO ALIVIO RD M3100 9 speed rear derailleur delivers a low profile design that lets you ride aggressively with fewer interruptions thanks to its SHIMANO SHADOW design. The SHIMANO ALIVIO M3100 2x9 speed or 3x9 speed drivetrains receive new updated shifters and derailleurs. SHIMANO ALIVIO utilizes Shimano hallmark technologies including SHIMANO SHADOW RD derailleurs and RAPIDFIRE PLUS MONO technology in the left shifter to simplify the riding