LED Digital Frequency Meter, 30-500 HzProduct Details:3.5 Digit LED Digital Frequency MeterFrequency Range: 30-500 HzInput Voltage Range: 30-500 Volt ACPower Voltage for LEDs: 8-16 Volt DC (Can Usse 9 Volt Battery)Total Size 3.1″ (W) x 2.3″ (H) x 2.3 (D)Panel Cutout Size 2.14″Material: PlasticColor: BlackUsed Widely in Control System, Mechanical Equipment, Shipbuilding, Aviation, etc.BocatechBTDPAHL-HZ-M