my two prong center has a probe (like a ice pick)between the two prongs, the probe is removable
when do i leave it in and when do i take it out,
any guidelines
i use the two prong center on cross garin and 4 prong center on endgrain
when do i leave it in and when do i take it out,

i use the two prong center on cross garin and 4 prong center on endgrain