Abstract: A base made from plastic material for a motor vehicle tank accessory, including protrusions to be welded to a preform during production of the tank by blowing the preform, wherein: the base includes a solid surface recessed from the protrusions, the solid surface including a part without protrusions and a part taken up by the protrusions, the area of the part of the solid surface without protrusions is at least equal to one times the area of the solid surface taken up by the protrusions, the height of the protrusions relative to the solid surface is between 0.6 mm and 0.8 mm.