SY-N2 is a LCD self-powered digital tach/hour meter, with powerful microprocessor and memory techniques. It keeps track of true engine RPM and running time for all types of engine. No matter gas engine or diesel engine. The operation can be triggered by either spark plug signal of engine or transducer of engine shaft or motor reel and magnetic signal. It has three different mounting ways according to different operation principle. This is useful for maintenance and warranty applications for any type of engine-powered machinery. The unit is powered by an internal lithium battery. No external power connection is required.