This 904949 maintenance kit is fits for Porter cable FN250B Type 1 and FN251 Type 1 nail guns, perfectly matching the original part specifications to ensure efficient replacement and long-term equipment stability. The kit contains precision machined springs, sealing rings, and key durable components, all of which have undergone strict quality control, wear resistance, and high pressure resistance, greatly extending the tool's service life. Quickly replace without the need for professional tools, simplify the maintenance process, reduce equipment downtime, help you quickly restore construction efficiency, suitable for daily maintenance and fault repair. By restoring the original air pressure transmission efficiency and firing force of the nail gun, the continuity of the operation is ensured, and problems such as nail jamming or insufficient power are avoided. It is suitable for high load professional engineering environments. each component undergoes compatibility and safety testing to ensure seamless collaboration with FN250B and FN251 models, providing reliable after-sales support.