1,Piston surface hardness: 1000hv 2,From STD to 2.00 Oversize 3,Rings suface: chromeplate, nitridize 4,OEM service Our company is a specialized supplier for motorcycle spare partsModels include:YAMAHA: JOG50, SR50, HORIZENTAL, VERTICAL, YB50, YB80, YB100, JY55, CX50, V50, V80, V90, COMET, CPI, T50, NF50, NF55, NX50, AXIS90, AXIS100, RS100, DX100, SRZ150, YBR125, Y110, XH100, LC100, DX100, YAMAHA ...