The PET-304 by Oppama is a compact digital combination tachometer/hour meter designed for use on single cylinder, 2 or 4-cycle gas engines. Can be used non-contact (wireless) or wired with the included clip-on lead. Measures RPM from 100-20,000 with +/- 10 RPM accuracy, with a 0.5 second refresh rate, measures running hours up to 10,000 hours. Other specifications: 20,000 running hour battery life (non-replaceable), weight: 1 ounce, dimensions: 1.6" x 2.3" x 0.5" Made in Japan by Oppama, Echo branded