MAG-DRO's caliper base is a magnetic device used to fix calipers easily to any flat, unpainted steel work surface for quick and accurate adjustments to machines such as table saws, planers, and routers (using an angle plate) 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