This caliper is the 3-key digital variety, and has a range of 0-12". (0-300mm). Has on/off function and a zero setting in any position.* 12" long or 300 mm long | stainless steel - hardened | simple on and off button * Fine adjustable thumb wheel allows movement of the scale more precisely * Inch/mm reading - 0.0005" - 0.01mm precision | locking screw to keep position * Zero setting button allows you to calibrate the caliper to 0 at any point * Battery included (1.5V LR44) | a very sleek and elegant looking caliper!