These Counterbalanced high-quality stainless steel shaft extensions feature a deeper penetration depth (3") vs. standard steel extensions to help keep swingweight increases at a minimum while extending golf clubs. The 12" long extensions are made of stainless steel for durability and have been swaged at both ends to allow each extension to be used in two different golf clubs. The 3" insertions depth also allows for greater surface coverage when using epoxy to secure the extension for a more secure fit.  You can always shorten the insertion by up to an 1 1/2" if your extension is 1" or less. Fits .600" butt shafts, which fits most True temper, Project X, KBS or Nippon shafts.  Does not fit most putter shafts.