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 outside of the building. This option includes: Digital RM3 N Female Omni-Directional, tamper resistant antenna and all necessary hardware to remotely mount the AlarmAgent WRTU up to 18" from the inside of the cabinet and the Digital RM3 upto 10' from the outside of the cabinet. Requires a 5/8" diameter hole for antenna connector. suggested when the AlarmAgent WRTU is in the NEMA 4X enclosure and mounted inside a cabinet.