A shock absorber utilizes an array of restrictive rebound fluid flow passages radially formed in a piston assembly. The flow passages are defined by a relatively narrow entrance and a relatively wide exit. A contoured wall form one wall of the passage. The restrictive rebound fluid flow passages restrict the flow-through of rebound fluid. The damping characteristics of the shock absorber are determined by the restriction caused by the general shape of the passages. Because restriction produced by the passages is a function of the contour of the passages and the entrance and exit widths, virtually any damping curve may be achieved by forming a passage having a selected contour.