A touch fastener has a base and an array of discrete fastener elements each extending from the base and together forming with the base a contiguous mass of resin. Each discrete fastener element includes a stem rising from the base, and a head overhanging the base from a front side of the stem to a distal edge, the front side of the stem, an underside of the head, and an upper surface of the base together forming, in side profile, a generally curved retention space boundary surface such that the boundary surface forms, at its innermost extent, a retention cavity defined between curvature discontinuities spaced from both the base and the distal edge.