Spring for roll stop or trolley stop MECHANICAL to Dhollandia. It is mounted in all the clamps produced after 2005 and under each flap there are usually 3 pcs. Their shape as seen in the photo resembles a V. You understand that you are in the presence of a mechanical stop because, for the opening, there is a metal tab that must be stepped on with your foot. Doing this imprints the first movement to the flap that then thanks to these 3 springs rises instantly. ATTENTION: Dhollandia has another system of truck-stops called "AUTOMATIC" which mounts springs similar to this one but slightly different. The AUTOMATIC system has one of the two arms of the slightly raised V, while the springs of the MECHANICAL system are completely flat.