Cylinder Piston Piston Ring Kit High Compression Gas Power Assembly 43mm Replacement With Pin For HUSQVARNA 545 550XP Feature:1. Lightweight high-silicone aluminum alloy provides strong heat dissipation ability, very useful2. The thermal conductivity is increased by 42% compared with the bimetal structure, has good thermal matching with the piston, and reduces the weight of the whole machine3. One-piece molding, increase the strength of the machine body and improve the surface hardness4. Greatly enhanced wear resistance, corrosion resistance and high-temperature impact resistance, strong and stable5. Strong gas compression ability provides rising power, clear thread and smooth knob, not easy to jamSpecification:Item Type: Piston KitMaterial: High Silicone Aluminum AlloyPiston Diameter: Approx. 43mm/1.7inPackage List:1 x Piston1 x Piston Wheel2 x Piston Ring1 x Piston Pin