The invention relates to a damper having a damper cylinder, in which a piston plunger (11) is guided via a piston rod (12), wherein for the adjustment of characteristic damper values the flow of a damper fluid can be controlled via control means disposed inside the damper cylinder, wherein the control means controls the flow of the damper fluid in a first flow direction using first adjusting means (34) and in a second flow direction using second adjusting means. According to the invention, the first and second adjusting means are provided with at least one spring element (34, 34, 51), wherein the spring rate of at least one of the spring elements (34, 34) can be adjusted for defining a damping behavior using corresponding defining means (35, 35).