this is a Maryland State inspection... you must have one in order to buy/sell a vehicle, and the inspection is only valid for i believe 60 days.
further, the state authorizes certain "mechanics" (con artists) to rip you a new one every time you have to get a vehicle inspected.
and FYI i've been to THREE different inspection places and the FIRST thing they say is "dem tars too beeg <spit>"...