Features: Tachometer is one of the necessary instruments for machinery industry which is used to detect rotate speed linear velocity or frequency of motor. It can precisely measure rotate speed of impeller blade expansion cylinder and spindle and can be widely used in motor fan washing machine textile automobileairplane ship and other industries. Specifications: *Measuring Range:2.5~99999 rpm *Resolution: 0.1 rpm (2.5~999.9 rpm) 1 rpm (1000~99999 rpm) *Accuracy: (0.1%n+5d)rpm;(2.5~999.9rpm) (1%n+5d)rpm;(1000~99999rpm) *Laser Power: CLASS2II2-5mW *Sampling Rate: 1 time / second *Measuring Distance: 50-500mm *Time Base: Quartz Crystal *MAX. MIN. AVG. and LAST Value *Operating Environment: 0~50C ;32~122F ;10%~90%RH *Storage Environment: -10~80 C;-14~176F;10%~75%RH *Auto Power Off: One Minute Without Any Operation *Power:2*1.5V AAA Batteries(NOT Included) *Weight:97g *Dimension:127*55.7*27mm Package included: 1 x Rotation Speed Digital Tachometer