The EstwinThe Estwing RPEFR2190 Replacement O-Ring, Drive Blade and Bumper Kit includes the drive blade and bumper needed to rebuild and repair the internal firing unit of the Estwing EFR2190 21 Degree Framing Nailer. This kit uses high quality heat-treated steel, aluminum, rubber, and plastic construction for long lasting durability. The light weight of the components reduces fatigue while working. Refer to the parts diagram for part number identification and installation.g RPEFR2190 Drive Blade and O-Ring Replacement Kit includes the O-rings, drive blade, and bumper needed to repair and replace the Estwing EFR2190 Framing Nailer's internal wearable parts. This kit includes an O-ring kit (parts 6, 8, 9, 10, 13, 14.1, 17, 19, 25, 27, 48.4, 65) and a drive blade and bumper kit (parts 14, 21). For parts identification, parts diagrams can be found at PrimeGlobalProducts.com.