1. Fitting: for GX390, GX 390, GXV390 13HP 2. PRECISION MACHINED FOR PERFORMANCE: Our chainsaw piston ring kit is carefully designed to deliver performance in your chainsaw. Made from quality materials, this chainsaw piston ring bolt kit ensures precise fit and reliable operation. 3. DURABLE CONSTRUCTION FOR CONTINUOUS USE: Our trimmer piston ring pin kit is designed for tough use and engineered to withstand the demanding conditions of chainsaw operation. The robust construction of the chainsaw piston kit resists wear and tear, helping maintain chainsaw performance even in challenging environments. 4. ENHANCED COMPRESSION FOR IMPROVED PERFORMANCE: The chainsaw piston kit improves engine compression, which enhances overall performance and efficiency. With improved compression, your engine operates more smoothly, offering quieter running and increased cutting power.