Evolution Gun Works Ignition Kit w/Lightened Hammer and 17 Number Main Spring. Our hammers should not be coated by applications that require the product to be heated. These coatings heat the hammer and can cause the hammer to become brittle.Some coatings such as Robar's NP3 will work fine but please consult the coater before to make sure the process is safe for heat treated components.Coating The Hammer can Lead To Fractures And Will Void The Warranty. Kit includes: EGW HD Hard Sear EGW HD Hammer EGW Ball Head Disconnector Colt Sear Spring 17# ISMI Main Spring Works in STI/Stacatto 2011 s The Mainspring in our Ignition kits will not work with an Officers model or Defender. It will only work with mainsprings with an OAL of 2. Specifications for Evolution Gun Works Ignition Kit with Lightened Hammer and 17 Number Main Spring: Manufacturer: Evolution Gun Works Gun Make: 1911 Platform Condition: New Package Contents: Evolution Gun Works Ignition Kit with Lightened Hammer and 17 Number Main Spring Evolution Gun Works 10211-17: Ignition Kit w/ Lightened Hammer and 17 Number Main Spring