The great advantage of these calipers is that they are direct reading. Not only can you set the opening without reference to a ruler, you can also check dimensions quickly and easily, with measurements displayed in large, easy-to-read numerals on the LCD screen.
Both inside and outside calipers read in fractional inches, decimal inches or millimetres (to a resolution of 1/64", 0.01" or 0.1mm), and instantly convert among units. Quick-setting sprung legs help ensure that the tips maintain contact with the workpiece, and a thumbscrew locks the opening. Accurate to 0.01", the calipers can be zeroed for differential measuring, and a "hold" button keeps the measurement displayed after the legs are released, so you don’t have to commit it to memory.
The outside calipers have 4" legs with a 7" maximum opening; the inside calipers have 3-1/4" legs with a minimum opening of 1/2" and a maximum opening of just over 6-3/4". Each has a 4" handle and comes with two button-cell batteries (one installed and one spare).