Contact and noncontact Model HT-5000 uses visible light to measure anywhere on rotating body. Simply apply piece of reflective marker to body, and point tachometer. LED verifies position. Tripod-mountable unit measures in ranges of 6-99,000 rpm (noncontact); 6-20,000 rpm (contact) with 0-1 V FS analog output. Latest min/max values are held in memory and displayed on backlit LCD for 10 min. AA batteries provide 40 hr continuous use.