The Practical Instrument Electronics’ Model 541 is the best tool for calibration, test, and diagnosing turbine meters, frequency counters, vibration systems, tachometers, vortex shedders, integrators, and any other Frequency devices in the shop, plant and/or field. The Model 541 brings all the features you would expect from a frequency calibrator and timesaving new ones. The model 541 comes with an LED indicator showing gate time for easy trigger level adjustment. Make adjustments with the EZ-Dialä Knob or test limits with the dual action EZ-Checkä Switch. Save hours of troubleshooting time on problems when compared to other calibration methods. When calibrating a totalizer, the model 541 eliminates the need of a stop watch. This calibrator will automatically stop when the selected number of pulses has been sent to the totalizer.