Redding Bullet Seating Micrometers are for use with most standard Redding Seating Dies and provide a direct replacement for the original seat plug. They provide a direct replacement for the original seat plugs and can easily be changed from one die to another. Redding Bullet Seating Micrometers for bottleneck cartridges are available for traditional bullet shapes (STD) and for VLD bullet shapes (VLD). They are also available for handgun and straight wall cartridges with traditional bullet shapes (STD) and flat nose bullet designs (FLAT). Mfg: Redding