Md. Code, Business Occupations and Professions § 19–407

(a) Whenever a security guard is in uniform, the security guard may wear a badge that is:

(1) of a design approved by the Secretary; and

(2) issued by the licensed security guard agency or the security guard employer that employs the security guard.

(b) Whenever a security guard is in uniform, the security guard shall clearly display and wear the clearance card issued by the Secretary which identifies the security guard.