TZT EW135G4 SKM9000 Double Channel Wireless Microphone System Stage UHF Cordless Microphone System Specifications: – Frequency range: 620MHz-950MHz – Debug mode: FM – Modulation range: 25MHz – Channel spacing: 250kHz – Frequency stability: ± 0.005% – Dynamic range: 100 dB – Maximum deviation: ± 45kHz – AF Response: 80hz-15khz (± 3db) – Total signal-to-noise ratio: 105dB – Overall distortion: = 0.8% – Receive Sensitivity: 12dBuV (80dBS/N) – Total harmonic distortion. Usually it costs about 30USD-50USD. Thanks for your understanding. If you receive the item that not satisfied or defective, please do not open case and kindly notify us within 30 days.