A device which can slide up and down on a chain or cable, can be loosened to attach to the chain or cable, but does not have any parts that come free when the part is loosened. The device includes first and second pieces, each made of structural material, the first and second pieces fitting together at concave and convex surfaces, to form an interlock forms inner surfaces with a through hole of a first shape that can slide along either a cable or a chain.

A connector comprises a first coupling part having a flat surface with a shaft projecting therefrom; and a second coupling part having a corresponding flat surface and a hole, such that the flat surfaces may be in abutment when the shaft is inserted into the hole and the first coupling part is positioned transverse to the second coupling part. The first coupling part is movable relative to the second coupling part from a position in which the shaft is inserted into the hole to a position in which the coupling parts are held so as to be inseparable by the shaft being captured inside the hole. The first coupling part is rotatable relative to the second coupling part about the shaft when the first coupling part is in the position in which the coupling parts are held so as to be inseparable. The first coupling part and the second coupling part are provided with load transference surfaces arranged to transfer load forces between the coupling members when the first coupling part is rotated relative to the second coupling part to an engaged position.