Abstract: A safety-pin is provided with a sheath (16;33) that fits over the cap (12;28) of the pin and can be slid between a release state and a locking state. During assembly the sheath is slid onto the cap and then at least one lug (21A,21B;38) on the sheath is bent to prevent subsequent removal of the sheath, and another deformable part (22A,22B;39)of the sheath is deformed to engage the cap sufficiently tightly as to prevent unwanted movement of the sheath. The sheaths can be slid onto the caps in either of two different ways and have redundant lugs (20A,20B;37) and deformable parts (23A,23B) so arranged that whichever way a sheath is oriented relatively to the cap, it has a lug or lugs and a deformable part suitably positioned for deformation. The sheaths are therefore fitted to the caps randomly orientated. The cap may be single-sided (28) or double-sided (12).