Amazon: Tiny Tach Wireless handheld Tachometer wwwon››Electrical›Gauges›TachometersBuy Tiny Tach Wireless handheld Tachometer Lawnmowers Chainsaws Trimmers Fast Tach: Tachometers - Amazon FREE DELIVERY possible on eligible purchases3.5/5(5)Price: 100 Handheld Tachometers - Tiny-Tach Specifications. Reads engine speeds up to 10,000 RPM with accuracy of +/-1 RPM. Clamp-on universal transducer supplied for diesels fits 6mm, 1/4 and 7mm, other size options available. Self-powered operation with no battery cables to hook up. Low operating current insures long internal battery life. Automatic shut off.