Applicable: handlebar diameter 31.8mm Installation tool: T25 screw wrench Computer used: GARMIN edge 200/500/510/800/810/1000 computer bryton RIDER 20/30/40 Chronograph IGS: iGS20/216/50/60/618 Blackbird BB10 /BB10S Stopwatch   ※ SRAM new listing, plastic-steel computer extension seat! ! ※Compared with the metal extension base, it is easy to scratch the plastic of the computer base when disassembling. ※In addition to the reinforced design on the back, the weight of this model has also been reduced a lot, only 19g. ※Long-term disassembly and assembly can easily cause the stopwatch card to loosen, causing the stopwatch to jump... This is also the reason why the stopwatch extension seat launched by SRAM is made of plastic steel.