MODEL:DT-2858 MEASUREMENT RANGE ROTATIVE VELOCITY: 2.5～99,999r/min (PHOTO) 0.5～19,999r/min (TOUCH) SURFACE SPEED:0.05～1999.9m/min 0.2～6560ft/min RESOLUTION:0.01/0.1/1 ACCURACY:±(0.05%n+1d) MEMORY: MAX/MIN/LAST VALUE POWER SUPPLY:4X1.5V AA(UM-3)BATTERY DIMENSION:215X74X32mm