Use the .255 Hex for crimping the rear ferrule to the following coax types:
RG-8X Belden 9258
RG-59 Belden 8241
RG-6 Belden 7916A
LMR-240
LMR-300
RG-62 RG-223
Use the .213 Hex for crimping the rear ferrule to the following coax types:
RG-58 Belden 9201
RG-58A/U Belden 8219
LMR-195 Belden 8259
LMR-200
RG-142
RG-400 Belden 7807