This industry comprises establishments engaged in (1) selling security systems, such as burglar and fire alarms and locking devices, along with installation, repair, or monitoring services or (2) remote monitoring of electronic security alarm systems. Cross-References. Establishments primarily engaged in-- ? Selling security systems for buildings without installation, repair, or monitoring services--are classified in Sector 42, Wholesale Trade or Sector 44-45, Retail Trade; ? Retailing motor vehicle security systems with or without installation or repair services--are classified in Industry 44131, Automotive Parts and Accessories Stores; and ? Providing key duplication services--are classified in Industry 81149, Other Personal and Household Goods Repair and Maintenance.