Battery-Operated KAB Speed Strobe Makes Checking and Adjusting Turntable Speed a Breeze: Displays Numbers Directly on the Disc, Operates with Dead-On Accuracy Simple to use, dead-on accurate, and featuring its own battery-operated hand-held strobe light with a precision quartz-controlled circuit, the KAB Speed Strobe makes checking and adjusting turntable speed a breeze . Simple and fun to use, it displays the speed numbers in easy-to-read sizes directly on the disc , which is silk-screen-printed on durable 20-mil PVC. Plus, by timing the drift of the display over the course of one minute, you can even measure fixed-speed turntables and determine their accuracy with uncanny exactness. From a technical perspective, the best-selling KAB SpeedStrobe improves upon older strobe designs that relied on power-line frequency and hypnotic bars that "freeze" in motion. KAB also wanted something easier to use and included the ability to measure small amounts of error. As such, it relies on a quartz-locked illuminator with 99.99% accuracy. And since it is battery operated, it works everywhere. 100% Music Direct Guaranteed.