Features: - Contactless mode for measuring from a distance of 50 to 500 mm - 5-digit LCD display with 18 mm high characters - Compact and lightweight housing made of durable ABS plastic - Easy operation with infrared beam and reflective tape - Multipurpose in engines, wheels, cutting machines, electric fans, etc. Specifications: - Test range: 2.5 rpm ~ 99,999 rpm - Resolution: 0.1 rpm (2.5-999.9 rpm) / 1 rpm (over 1000 rpm) - Measurement accuracy: ±(0.05% +1) - Sampling time: 0.8 seconds - Effective measuring distance: 50 mm ~ 500 mm - Time base: 6 MHz quartz crystal oscillator - Power supply: a single 6F22 9V battery (not included) - Power consumption: approximately 35 mA - Instrument size: 131×70×29mm - Weight: 142g Notes: - It is recommended to stick the reflective tape on the target object before measuring - Do not aim the laser beam directly at the eyes - Do not use near explosive gases or in explosive areas