Forming a fastener component having heads constructed to engage loops formed e.g. of fibers of a mating component, comprises forming, from a thermoformable material, a preform product having a sheet-form base and an array of preform stems integrally molded with and extending from the base to corresponding terminal ends, by a process having a machine direction and a cross-machine direction. Each molded stem has at least two terminal features spaced from one another in the cross-machine direction, the features having a transverse shape about which engaging fibers can bend, the features having a thickness of about 0.25 mm (0.010 inch) or less, preferably about 0.20 mm (0.008 inch), and for personal care products and the like preferably about 0.1 mm (0.004 inch) or less. The terminal ends of the features are heated to a predetermined softening temperature and the terminal ends are contacted to reform the terminal ends to form heads therefrom that overhang the sheet-form base sufficiently to engage loops.Also shown are molded stems that have at least two terminal features spaced from one another in the machine direction; molded preform having substantially parallel side surfaces on all sides, e.g., of “M” or crossed “M” profile of substantially thin fin or crossed thin fin form of molded stems that carry upwardly directed, spaced apart prongs.Preforms are shown having at least three prongs along at least one coordinate. Each prong of a group of at least two neighboring prongs is coalesced to form a head or all prongs of a stem are coalesced to form a single head.