WSM Piston Kit - Yamaha 660 - +1 mm 50-544-07K 100 percent Bio-Flex knee and optional Bio-Flex

Bio-Flex knee and optional Bio-Flex hip armor for high levels of impact protection

Alpinestars integrated Transversal Protection Frame (TPF) protects the foot while delivering the necessary support on the footrest without compromising the front foot flexion for superior walking comfort

shoulder and elbow pouches for optional armor

Wordmark camo graphic print on front

WSM Piston Kit - Yamaha 660 - +1 mm 50-544-07K 100 percent Bio-Flex knee and optional Bio-FlexPiston Kit Yamaha 660 +1 mm Quality and construction that meets or exceeds OEM, Feature improved E clip design, Contain piston, rings, pin and clips, Additional rings available separately, Order one per cylinder, Skirts have a nonabrasive, expansion retarding MOS2 coating to reduce heat and friction for added power and longevity, MOS2 coating actually draws heat through piston walls and out the bottom, Specially hardened tops add strength to ring