Abstract: A barb for engagement with a body 13 of deformable material such as nylon has a sharp edge 28 at the top of a relatively steep face 29 forming one side of a trough 32. A ledge or rim 38 projects from the face 29, about halfway up the face 29, and provides an abutment which restricts the extent to which the deformable material can enter the trough. This improves the resistance of the barb against being pulled out of the trough. This form of barb is particularly applicable to fasteners of the type in which a threadless bolt having barbs is embedded in a shell carrying a nylon sleeve.The barb is manufactured by a rolling process in which two dies are successively applied to a cylindrical blank, the first die to form the trough 32, and the second die to form the ledge 38.