TACHOMETER The Extech Combination Tachometer + IR Thermometer provides wide photo and contact RPM measurements, and contact linear surface speed measurements. The meter uses a built-in IR thermometer with a laser for measures on remote surface temperature of motors and rotating parts. The wide temperature range of -4 to 600°F (-20 to 315°C) has a an accuracy to 0/05% with maximum resolution of 0.1rpm in either photo or contact mode. The non-contact photo tachometer uses a laser for greater measuring distance up to 6.5 feet. The memory stores min/max/last data points. Specifications:  Display counts: 99,999 count LCD Range (rpm): photo: 10 to 99,999/ contact: 0.5 to 20,000 ft/min: 0.2 to 6560 (contact) m/min: 0.05 to 1999.9 (contact) Basic accuracy: +/-(0.05%rdg+1 digit) Maximum rpm resolution: 0.1rpm Temperature (IR): -4 to 600°F (-20 to 315°C) Dimensions: 8.5 x 2.6 x 1.5" (216 x 66 x 38mm) Weight: 10.6oz (300g)