Magnetic pick up powered tachometer.

TACHOMETER: signal-powered, 4- digit, intrinsically safe, unlighted display

The SPD-100 is a solid- state, intrinsically safe tachometer. The gate time range (0.26 to 5.70 seconds) is field- programmable. It is well- sealed for rugged indoor and outdoor applications. It has 4-digit, unlighted, LCD display.
Dynalco