Central Tools Company, high quality made in Japan 4 piece telescoping inside gauge set with original plastic pouch and box. I purchased these off a Snap On truck many years ago, they have been used very little, taken good care of, tension always released when not in use and stored in climate controlled shop. 

These are sometimes called snap gauges. They are in very good plus condition and work properly and smoothly, makes taking inside measurements simple. Self-centering and well made. The contact points release or lock by turning the knob at end of the handle.

The 4 gauges cover a measuring range of  5/16 of an inch up to 2 1/8 inch.