100% Brand New Items, Never Used or Installed. Designed and tested to meet or exceed OE standards and performance. Cylinder: Standard 86.50mm Bore. Piston: Compression Ratio 9.9:1. Gaskets: High quality and provide a perfect seal between all components. Professional installation is highly recommended. Instructions NOT included. Replace part number. Base Gasket: 12191-HP5-601 Retaining Rings: 13112-MAT-000 Cylinder: 12100-HP7-A00, 12100-HP5-600 Head Cover Gasket: 12315-HP5-601 Piston: 13101-HP5-600 Head Gasket: 12251-HP5-601,12251-HP7-A01 Piston Rings: 13010-HP5-600 Piston Pin: 13111-HP5-600 Kit includes: 1x Cylinder, 1x Piston Ring Set (Piston, Piston Rings, Pin, Retaining Rings(2)) 1x Head Gasket, 1x Base Gasket, 1x Head Cover Gasket As shown in the photos. Installation for Honda TRX420 Rancher 420 2007-2018.