Pick up a telescoping gauge set from Grainger to help you accurately determine the size of holes, slots and recesses. These gage sets include from 4 to 6 different sized tools to let you choose the appropriate sized gauge. Position the plunger inside the opening you need to measure and expand it to the edges. Then measure over the contacts with a micrometer. Each telescoping gauge set from Grainger includes a plastic case. Get yours today!