The iVision+(IVP-DH) gives you the ability to not only know when somebody is outside your door, but to view and talk to them from the safety and comfort of any location inside your home or business. The iVision+ wireless intercom package includes a convenient wireless handheld unit with LCD monitor and a wireless doorbell/camera unit with over 330ft. transmission range, line of sight. OPTEX has also taken the peace of mind offered from the previous iVision model and expanded it, now allowing for multiple handheld units, multiple doorbell/camera units and the ability to remotely release electronic door locks through a gateway/chime unit.