The Hornady Lock-N-Load Powder Measure Handgun Micrometer is the perfect accessory for the reloader looking to throw very small and very precise powder charges from the Lock-N-Load powder measure. The etched marks allow the reloader to dial in the exact powder charge in-between 0.5 grains up to 17 grains of powder and are very helpful when dialing to a favorite load. The micrometer pistol insert is made from steel for a lifetime of use and is 3.65" long. Notes: Must be used with the handgun rotor and metering assembly (Sold Separately, product number 164-839)