Measuring range: measuring range: 30 ~ 130dB Output: 485 output accuracy (23 ± 5 ℃): ± 7dB frequency weighting complies with IEC 61672 type 2 standard and is calibrated under the condition that the input signal is 94db (31.5hz – 8kHz). Frequency range: 31.5hz to 8kHz Frequency weighting: A, C weighting time response: fast response: T = 200ms Time response simulates the time response of human ear Corrector: B & K (Bruel & Kjaer), multifunctional sound calibrator, model: 4226 Microphone: condenser microphone Microphone size: 0.5 inches Range selection: 30 ~ 130dB, maximum output impedance: 200 ohms Power supply: DC 12V power loss: DC 12V: ≈ 20MW working temperature: 0-50 ℃ (32-122 ° f)