6pcs 40mm x 1.2mm piston ring set for FS400 MS210 ST021 MS230 ST023 MS201 MS201T MS211 chainsaw cylinder rebuild.Designed to fit specified models with consistent dimensions and performance.Each piston ring is inspected prior to shipment.Suitable for use in engine rebuilds requiring components.Package includes 6 pieces of piston rings. Compatibility Disclaimer: This is an aftermarket replacement part.Any brand names or model designations mentioned are used solely for the purpose of demonstrating compatibility.