Md. Code, Criminal Law § 3–403

(a) A person may not commit or attempt to commit robbery under § 3-402 of this subtitle:

(1) with a dangerous weapon; or

(2) by displaying a written instrument claiming that the person has possession of a dangerous weapon.

(b) A person who violates this section is guilty of a felony and on conviction is subject to imprisonment not exceeding 20 years.