Used with standard outside micrometers with spindle .256″DIA to measure pitch diameter of screw threads.
Diameter accuracy: ?20_in. Cylindricity: 39_in.
Cylindricity: 1um. Hardness: HRC60.
Supplied with manufacturer inspection certificate.
Supplied with manufacturer inspection certificate.

3M 19075, E-A-R Push-Ins Probed Test Earplugs 393-2002-50, 50 Pair/Case, 7000052881 