This kit assumes the AlarmAgent has not been shipped to the customer and is the Indoor Enclosure model. The AlarmAgent cabinet mount Digital YAGI antenna option is suggested when the AlarmAgent WRTU is mounted inside a cabinet and the antenna needs to be located outside of the building. This option includes: Digital YAGI antenna and all necessary hardware to remotely mount the AlarmAgent WRTU up to 18" from the inside of the cabinet and the Digital YAGI up to 30' from the outside of the cabinet. Requires a 5/8" diameter hole for antenna connector.