TheSpeco Technologies CAMMIC High-Impedance Line Level Microphone with 1.5' Cableis an add-on mini microphone that can be connected to an amplifier or DVR via a line level input instead of a microphone level input. This provides flexibility on amplifier or DVR units that have all their microphone inputs occupied or don't have a microphone input at all. This microphone is suitable for recording channel-specific audio on DVRs which offer that capability.