The TECHT G3 Spec-R/ G4 L7 Bolt Engine totally reconfigures the Stock G3 Spec-R/ G4's method of operation. By replacing the stock style bolt with our proven L7 style bolt head, performance is increased on every level. Lower operating pressure, shorter dwells, better consistency, better efficiency, lower sound signature...the works. The new TECHT G3 Spec-R/ G4 comes with a lifetime warranty, as do all TECHT products. It is constructed of high grade aircraft aluminum and goes through our licensed anodizing method to make them both durable and great looking. The TechT G3 Spec-R/ G4 L7 Engine Bolt includes a completely new "tool-less" backcap, as well a jewel decal to let everyone know to stay out of your way. Unleash your G3 Spec-R/ G4's full potential with an L7 Bolt Engine.