ITEM NAME:SRT-11A Waterproof IP65 Car Digital Gauge Engine Tachometer Tachometer Oper P9F6 SRT-11A Waterproof IP65 Car Digital Gauge Engine Tachometer Tachometer Oper P9F6 Show both engine speed and operating hours. Works on 2 or 4-stroke petrol engine. Programmable maintenance interval setting. Waterproof IP65. Battery can be replaced. This LCD Tach / Hour Meter is for keeping track of the engine speed and operating hours of machines, such as motorcycle, ATV, snowmobile, boat, generator, etc. It is for the maintenance of your applications. All you have to do is to put the battery in and wrap the wire 3 or 4 turns around the spark plug cable Color: Black material: plastic speed range: 300 ~ 30000rpm speed accuracy: 10 rpm battery: CR2450 battery life: about 2 years item Size: about 7.4 x 4.7 x 2cm / 2.9 x 1.8 x 0.8 In package list: 1 x User Manual 1 x Battery 2 x self-locking nylon cable ties Zip Note: This Tach / Hour Meter works for motors only, do not use spark plugs on crude oil engine engines. Note:Light shooting and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3 cm..Waterproof IP65. 2 x self-locking nylon cable ties Zip. Works on 2 or 4-stroke petrol engine. All you have to do is to put the battery in and wrap the wire 3 or 4 turns around the spark plug cable. battery life: about 2 years.