The STIHL 11270302005 Piston D49 is an original equipment manufacturer (OEM) replacement part designed for specific STIHL chainsaw models. This high-quality piston, with a diameter of 49 mm, is crucial for maintaining the performance and longevity of your chainsaw's engine. It is a direct fit for STIHL MS 290, MS 310, and MS 390 chainsaws, ensuring proper combustion and reliable operation. Made to STIHL's exacting standards, this piston guarantees durability and compatibility with your machinery.