Md. Code, Transportation § 13–945

(a) Special registration plates issued to the owner or operator of special mobile equipment under § 13-624 of this title are Class 4 (mobile equipment) registration plates.

(b) For each Class 4 (mobile equipment) registration plate, the annual registration fee shall be established by the Administration.

(c) A Class 4 (mobile equipment) registration plate may be used only on special mobile equipment owned or operated by the person to whom the plate is issued, and only as permitted by § 13-624 of this title.