Piston Ring for ECHO CLS5000, CLS5010, RM5000, SRM520, SRM5000...
Amazon.com: String Trimmer Parts 21560056 Universal Rapid-Loader Two Line Head Includes Adaptors for Echo Fits GT-225 GT-230 SRM-315 SRM-5000 CLS-5810 SRM-4605 + (Free Two E-Books) : Patio, Lawn & Garden