The Lyman Pro Micrometer Taper Crimp Die gives you exact the amount of crimp that you want. The Taper Crimp Die has a micrometer adjustable head for precise positioning of the floating crimp sleeve. If you want to change your bullet crimp a few thousandths of an inch, simply turn the micrometer head to the required setting. The floating crimp sleeve centers the cartridge and applies a perfect taper crimp. The Pro Micrometer Taper Crimp Die is also made of corrosion resistant stainless steel which protects it from rust and keeps it looking like new for a lifetime of use.