The Metrix Plus 19999 RPM Digital Tachometer is a contact tachometer used to measure any machinery or equipment's rotational speed. The battery-operated 19999 RPM Digital Tachometer is very lightweight and easily portable. All measurements are displayed on the backlit LCD screen. The RPM Digital Tachometer by Metrix Plus provides a data hold feature that comes in handy for quick recall of measurements. The recommended temperature condition to operate the device is 0 C to 50 C, and recommended storage temperature is -20 °C to 60 °C. The battery-operated device comes in a box with a user manual. Product Specifications: Manufactured by: Metrix Plus Product Code: 2235B Product: Contact RPM Digital Tachometer Contact: 0.5 - 19,999 RPM Linear Rolling speed: 0.05 - 1999.9 m/min Surface speed: 0.2 - 6560 Ft/min Accuracy: ± (0.05% + 1word) Sampling Frequency: 0.8s Power: AAA x 3 batteries Product Net weight: 150 g