These black anodized steel contact points are tapered to a rounded end which has a radius (SR) of approximately .025". The angle of the taper changes depending on the length of the point. At its widest point, the base, it will measure 5 mm. Although designed for Mitutoyo dial indicators, these will fit any other brand of indicator. Just be sure to select the correct thread size. American made.
MITUTOYO
Good stuff at reasonable prices