High-Quality Cast Aluminum Piston for Superior Strength to Weight Ratio Complete Standard Sized Piston Kit Including Gaskets 86.50mm Bore, 9.9:1 Compression Ratio OEM Style Gaskets to Allow for Breezy Piston Installation Good Quality and Performance Guaranteed Fitment for Honda Rancher TRX420 For Honda 13101-HP5-600, 12191-HP5-601, 12251-HP7-A01, 12315-HP5-601 Package Included One set of Piston kit (as the picture shown)