EntryVue VD-950 Video Intercom System Combo Set - 1 door station C + 1 P7 black monitor Monitors are equipped with internal picture memory capabilities.Every time a visitor rings your door bell the monitors will automatically store a picture allowing you to review all daily guests. The door stations come equipped with a high resolution Sony CCD camera with a wide angle view lens. Customize the setting of each monitor separately, such as volume, brightness etc. You can choose from a day time ring tone (high volume) and a night time ring tone (lower volume) 2 Wire System: Convenient when replacing an existing audio intercom system with a video intercom system. Simply daisy chain the monitors throughout the house. We recommend 2 X 18 or 2 X 14 gauge wire, stranded, not shielded (speaker wire.) Night vision: When someone rings your door bell at night the LED lights on the door station will automatically light up allowing you to have a clear view of your guest.