The Starrett 579 Telescoping Gage is used for determining the true size of holes, slots, and recesses. The ends of both contacts are hardened and ground to a radius to allow proper clearance on the smallest hole the gage will enter. The tool must be slightly rocked in the hole being measured to ensure that the tool is on the proper diameter before it is locked and withdrawn. The final hole size is obtained by measuring over the gage contacts with a micrometer.   Made in USA.
,For California Residents:,   WARNING: Cancer & Reproductive Harm - www.P65Warnings.ca.gov,WARNING: Drilling, sawing, sanding or machining wood products can expose you to wood dust, a substance known to the State of California to cause cancer. Avoid inhaling wood dust or use a dust mask or other safeguards for personal protection. For more information go to www.P65Warnings.ca.gov/wood Starrett 579F Telescoping Gage