frequency meter, device for measuring the repetitions per unit of time (customarily, a second) of a complete electromagnetic waveform . Specification: Model number: 99T1 Accuracy level: 1.5 level and 2.5 level External dimensions: 48x48 mm Perforation dimensions: 45 1 0 x45 1 0 mm Matched current transformer: 99t1-A:BH-0.66-30 Dielectric strength: 2KV 50Hz for 1min Work position: Vertical Operating temperature: -20 to 40 ℃ (-4 to 104 ℉) Package includes: 1 x  99T1-5A Indicator Type AC 5A Frequency Meter AC200-500V