Only the EURO TOOL 9-1/4" digital caliper comes standard with a stone holding plate attachment for easy measuring of loose stones, watch crystals, beads, etc. With the touch of a button you can convert measurements from millimeters to inches and back with accuracy to .01mm. The measuring system is a non-contact linear CAP with LCD display and an auto-off system to save the battery. Caliper will measure inside, outside or depth and features a fine adjustment thumb wheel and zero set button. This caliper comes in a protective nylon carrying case with foam padding and one spare battery. Maximum opening 6" (150mm).