Starrett
For accurately measuring small holes, slots, grooves and recesses. Hardened contact surfaces have split ball, which is adjusted to size by knurled knot at end of gauge. Final size in 1,000ths of an inch is obtained by measuring over ball contacts with a micrometer.
Includes 4 sizes (.125" to .500") and case.
WARNING: This product can expose you to chemicals including lead which is [are] known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.