The lowest frequencies that the mic can pick up well. Better for recording bass. If a microphone is going to be used for speech, a voice microphone, it must have great gain for bass, since human voice is in the low frequencies.
Sennheiser Presence UC: 6.8Hz
16. maximum bluetooth range
The device can connect at a greater distance via Bluetooth or infrared to another device.
Sena SMH10 Motorcycle Headset & Intercom: 900m
17. has a wind noise reduction microphone
The microphone reduces the sound of wind as it blows past device and disrupts the voice clarity.