Functions as a two-way speaker and microphone for M1 or M1 Gold systems Connects through the M1 2-Way Listen-In Interface Essential Info Add listening in and two-way voice verification options to your M1 Gold security and automation panel. The M1 Speaker/Microphone is a two-way speaker and microphone that allows you to listen in to your home or office in the event of a triggered alarm. The microphone connects to the M1 via 4-conductor cable through the M1 2-Way Listen-In Interface (sold separately). What's Included M1 Speaker/Microphone