part number: 904689. Package Includes: 1 Pack Seal-Head Valve, as the picture shows. Compatible with Porter Cable FN250B Type 1, FN251 Type 1, Nailer Parts. This part provides a seal for the Head Valve. This part install quickly to make your nailer work like new again. A brand-new, unused, unopened, undamaged item in its original packaging. Return refund: If you have any questions, you can refund in full without any problems