... Dynamic Range 100dB(1KHz at Max dB SPL)Maximum Level Input 120dB SPL (1KHz,THD 1%)Impedance 600ohm (imbalance) ... Detail Introduction:*F.TRADIO outdoor waterproof, shouting distance,directional audio surveillance mic,special design for ourdoor talkback, toll booth ... Selfrestraint high-intensity sounds, reliably protecting the back-end audio surveillance equipment* Low noise,low echo and clear speech, ...