Compatible with 154, 154XP, 254, and 254XP chainsaws. Durable cylinder and piston assembly - Engineered to withstand the high loads and temperatures of chainsaw operation - Efficiently transfers energy from combustion to mechanical motion for smooth operation and optimum cutting performance Premium piston material - Made from high-quality, wear-resistant materials for long service life under demanding conditions - Improves engine power and delivers reliable cutting performance in every task Efficient piston design - Precise fit and smooth operation reduce friction - Enhances overall engine efficiency, helps optimize fuel consumption, and promotes steady performance Use scenarios - Replacing worn parts during routine overhauls on 154/254 XP models to restore peak power - Prolonged cutting jobs in hardwood or sustained use where engine temps are high - Regular maintenance to extend engine life and ensure reliable performance in professional work