Replacement Part : This is a genuine quality replacement oil cap assembly for chainsaws, designed as an exact OEM matching for part numbers P021005581 and P021037920. Perfect Compatibility : Specifically fit for chainsaw models CS310, CS330T, CS352, CS355T, chainsaw models for versatile use. Complete Oil Cap set : Includes a oil cap assembly with retainer and separate O rings (requires customer installation) for proper sealing and maintenance of your chainsaw. Secure Installation Guide : For safe removal/installation, use an oil cap wrench or adjustable pliers wrapped in soft cloth to damage; avoid over tightening the component. Package includes: 1pc Chainsaw Oil Cap (with Retainer)