Check the listing for details. Lutron LF-423: Line Frequency Monitor. Condition: New. Listed at 71.99 USD. Model : LF-423* 0.5 to 500 Hz (x 0.01Hz, < 100Hz)* Input voltage : 5 to 250 ACV.* Check frequency to DC to AC converter, mobile & portable generator, power line.Features:* Portable line frequency monitor, easy carry out & operation.* Wide measuring rage from 0.5 Hz to 500 Hz. * 0.01 Hz, high resolution* Quartz crystal time base, 0.05 %, high accuracy.* Wide input voltage 5 to 250 ACV. * LCD display allows clear readout even at high ambient light levels.* Sine wave or square wave input signal are available. * Last value, Maximum value & Minimum value with recall. Applications:* Check output of frequency-regulated and unregulated DC to AC converters.* Verify accuracy and stability of synchronous motors & clocks.* Monitor frequency of mobile and portable generators under load. *Obtain the long term maximum, minimum & average frequency of fluctuating power sources.* Continuously monitor frequency in engineering and school laboratories when delicate experiments are performed or calibration of equipment is taking place. Display5 digits, 10 mm ( 0.4″ ) LCDSampling Time1 sec. ( 1 Hz ).Operating temperature0 to 50℃ (32 to 122 ℉).Operating HumidityLess than 80% RHWeight375 g ( 0.83 LB )/including batteryDimension190 x 72 x 37 mm (7.5 x 2.8 x 1.5 inch).Resolution0.01 Hz 0.5 to 99.99 Hz.0.1 Hz 100.0 to 500.0 Hz.Accessories IncludedOperation Manual…………………………………..1 PC.Power Cord with plug………………………………1 PC.