Optex iVISION+ Gateway Chime Unit for Door Release IVP-GU Allows the iVISION+ the ability to remotely release electronic door locks Allows forintegration of multiple handheld units, multiple doorbell/camera units with the iVISION+. Allows the camera on the door unit (iVISION+) to open when triggered by the Wireless 2000s sensor unit. Allows the iVision+ to integrate with the OPTEX Wireless 2000 (RCTD-20U) (sold separately)