These RCBS factory replacement decapping units are the same ones we ship with our products - so you can rest assured they will work. This unit features an expander rod and ball and a decapping pin. It's used with sizing dies to de-prime the case and expand the neck in bottleneck cartridges. Factory Replacement Part Precision Machined to ensure concentricity Expander Rod, Expander Ball and Decapping Pin .338 Taper Limited Lifetime Warranty Compatibility .338-06