Digital caliper-jaw micrometers are used to measure the inside dimensions of holes, tubes, pipes, or grooves. They have jaws that expand and contract with thimble actuation. These micrometers are held at a parallel angle to the surface of a hole or bore to measure diameter with contact points on the jaws. The LCD display is easy-to-read and does not require operators to do any math. They can also be used to measure the area beneath a groove or lip at the opening of a hole.