Piston Rings Assembly Set 277-23511-17 Compatible with Engine EX17 EX21 6HP 67MM 277-23513-17 This piston rings assembly set is designed for use with EX17 and EX21 engines.It includes all necessary rings for a complete rebuild, fitting models with 6 horsepower and a 67mm cylinder bore.The set replaces part numbers 277-23511-17 and 277-23513-17.Each component is engineered to meet specifications for proper sealing and compression.Installation requires standard tools and mechanical knowledge.This kit is intended for engine maintenance and repair applications. Disclaimer: This replacement is not affiliated with any manufacturer.Model references indicate fitment only.