This optical tachometer measures the true speed of propellers from within the aircraft—accurate to within 1 rpm! Just point it at the propeller or rotor blades and the tachometer immediately displays the rotational speed. Great for pilots, mechanics and homebuilders. Measures from 240 to 7000 RPM and works for propellers with 2, 3, 4 or even 5 blades. Compact size fits conveniently on your glareshield, and weighs just 4 oz. Uses one 9 volt battery (included).
Made in USA.