Features 1. Easy to use " Instant" intercom system 2. Individually call and group call function 3. Lock button (or monitor function) let you talk continuously 1 Hour 4.New Full Duplex Intercoms Wireless,Real Time Two-Way Communication Advantage Easy set up, no installation requirement. Can move to different room. Simple intercom system. One to one selective communication or one speak to all intercom simultaneously. Family Application Desktop use & wall mounted use. You can program different channel number for each intercom or at same channel number. You can choose one to one communication or one to all. You can use mobile power pack. Office Application You can program different channel for each room or department Group call can use for Emergency Notice and meeting use.