MAG-DRO's mitre slot base is a device used to fix calipers easily in a 3/4-inch slot, or the base can be clamped or screwed to a flat surface, for quick and accurate adjustments to machines, such as table saws, planers, and router tables. MAG-DRO enables fast and precise measuring using a fixed point. With virtually unlimited application in the shop, MAG-DRO reinvents the capabilities of calipers. BENEFITS: • Precise measurements - easier and faster • Save time in the shop, faster more accurate set • Adjust your cuts in .001 of an inch • Affordable