Doppler ER3 variator for Motobecane. Uses a unique rocker-arm weight setup as opposed to conventional roller weights. While rollers can wear and groove, rocker weights do not physically move on the variator resulting in smoother and more easily controlled variation. The weights are external so the hassles of removing or disassembling the variator to change weights on the fly is eliminated. Simply remove the weights with the included allen wrench and replace. The ER3 is also extremely light weight resulting in faster spool up off the line. Learn More