Gas spring assembly with selectable intermediate stop

A gas spring assembly is used to control movement of a vehicle body panel. The gas spring assembly includes a magnetic collar that allows an end user to position an intermediate stop position at a desired location. The magnetic collar is externally supported on a tube of the gas spring assembly. The end user selectively adjusts the intermediate stop position by moving the magnetic collar relative to the tube. The gas spring assembly includes a piston that is received within the tube and connected to a rod. The rod moves relative to the tube between a fully extended position and a fully compressed position. The magnetic collar includes a magnet that cooperates with the piston assembly to stop and hold the vehicle body panel at the intermediate stop position as the rod moves from the fully compressed position toward the fully extended position.