A C-class marking is the C0–C6 identification label a manufacturer attaches to a drone under Regulation (EU) 2019/945. Each class fixes specific limits — mass, speed and mandatory features such as geo-awareness, remote identification or a low-speed mode.
The class also determines which open-category subcategory the drone may fly in: C0 and C1 map to A1, C2 to A2, and C2–C4 to A3. Classes C5 and C6 serve the standard scenarios of the specific category. The label on the drone is therefore the first thing to check before planning a flight.