This industry comprises establishments primarily engaged in providing one or more of the following: (1) investigation and detective services; (2) guard and patrol services; and (3) picking up and delivering money, receipts, or other valuable items with personnel and equipment to protect such properties while in transit. Illustrative Examples: Armored car services Private detective services Bodyguard services Security guard services Polygraph services Cross-References. Establishments primarily engaged in-- ? Providing credit checks--are classified in Industry 56145, Credit Bureaus; and ? Selling, installing, monitoring, and maintaining security systems and devices (e.g., burglar and fire alarm systems)--are classified in Industry 56162, Security Systems Services.