Specifications: Power source: Cigar lighter or battery 915 VDC Measure Target: 2,4 stroke,1-12 cylinder Measurement range :400- 9,999 RPM Maximal error:< 20 RPM or relative 1 % Response time: < 1 second Dimension:144 x 98 x 40 mm Weight:350 g General Features: Used for engine's RPM measurement of gasoline, diesel, and natural gas. Directly connected to Cigar lighter or battery to measure its RPM without any sensor. RS-232 interface and LCD display. Universal, connective to any exhaust gas analyzer and Opacity meter. Standard signal interface Such as TTL or RS23 Products including: Gasboard-8010, Cigar lighter connection cable 5m, clamp(battery), RS232 cable, user manual. Optional accessories: RS232 cable clamp, cigar lighter power supply cable