This kit assumes the AlarmAgent has not been shipped to the customer and is the NEMA 4X model. The AlarmAgent cabinet mount Digital RM3 N antenna option is suggested when the AlarmAgent WRTU is in the NEMA 4X enclosure and mounted inside a cabinet and the antenna needs to be located on that cabinet. This option includes: all necessary hardware to remotely mount the AlarmAgent WRTU up to 18" from the inside of the cabinet and the Digital RM3 on the cabinet. Requires a 5/8" diameter hole for antenna connector