These machined aluminum split pliers are designed to loosen Redding dies when screwed into the press. These pliers fit the die body lock ring, which frequently is in a jammed fit with the die and the top of the reloading press. The smaller hole fits the smaller knurled lock nut on top of the reloading die that locks down the decapping assembly. The contoured fit of these pliers prevents the damage we routinely see on lock rings from handloaders using adjustable pliers.
Sinclair, Issue:4S, Page:014