PHYHOO Jewelry Tool Electric Dial Gem Caliper Gem Gauge millesimal 0.01/0.0005" Resolution:centesimal:0.01mm/0.0005" millesimal:0.001/0.00005" Measuring Range:0~12.7mm/.5",0~25.4mm/1" Power:one button battery(SR44/LR44)with work voltage 1.5V