Features:
Allows you to accurately adjust the speed of your turntable to 33-1/3, 45 and 78rpm.
Designed for use in artificial light, the disc's pattern will appear to be static when the turntable's speed is correct.
All you need to do it place the disc on your platter, turn on your light and then adjust your turntable's speed control until the pattern on the disc doesn't move.
Easy to use

Specifications:
Test turntable platter speed
Tests 33-1/3 rpm, 45 rpm, and 78 rpm speeds
Works on 50 Hz 

Package includes:
1 * Strobe light
1 * Tachometer disc
1 * USB cable

Note:
If the stripe of the LED light is stable and does not move, the speed is correct;
If the stripes on the disc move slowly clockwise, the dial runs very fast;
If the stripe on the disc moves slowly counterclockwise, the dial runs slowly.