Feature: 1. High quality, durable. 2. Perfect match for the original machine. 3. Easy installation. 4. Stable characteristics, high reliability. 5. Strict inspection before shipment for each one. Fits Husqvarna 154, 154XP, 254, 254XP Chainsaw Diameter: 45mm Replace Part # For 503503903,503 50 39-03 Package Include: 1 x Cylinder, 1 x Piston, 1 x Pin, 1 x Ring, 2 x Circlip.