The micrometer adjust screw by Lee Precision replaces the original adjusting screw on any Lee bullet seating die. Infinitely adjustable, allows precision bullet seating depth. Easy to read laser engraved divisions represent .001" one thousandth of an inch. The integrated friction ring eliminates annoying clicks that prevent splitting thousandths. No clicks, just smooth adjustment. Reads just like a precision depth micrometer, record your setting and easily return to them for future use. The micrometer adjuster can be easily transferred to other Lee Bullet Seating Dies, but it is so economically priced, you will want one for every die.Specifications and Features: Not sure which Micrometer you need? Search the manufacture website to reference the chart and match your bullet seating plug to one of the images: https://leeprecision.com/large-caliber-rifle-micrometer-adjust-screw