Sierra Tech Specs
Headphone Impedance:  OFF Mono-180 Ω, ON Mono-300 Ω, OFF Stereo-250 Ω, ON Stereo-600 Ω, All @ 1kHz

Speaker Frequency Response (Active) :20Hz to 20kHz (volume sliders max)

Microphone Electret: Bias: 8-16V (Not polarity sensitive), Bias Resistance: 220Ω-2200Ω

Sensitivity Electret: 20mV-80mV across 8-16V, Bias Re: 94dB SPL input at 6mm

Frequency Response: 200Hz-6000Hz

Maximum SPL for Microphone: 114db

Power Source: Battery: 3V, 2(AA) Alkaline batteries

Maximum SPL for ANR: > 120dB @ 100Hz

Weight:16 oz. / 453.59 grams, Bluetooth Enabled Phone, Bluetooth Streaming Music