Abstract: A locking device for securing at least two screw-action connectors comprises a locking clip or element made from a good quality spring steel wire having a round or square section. The locking clip or element has a diagonal interconnecting part which extends tangentially between a pair of locking elements one at each end of the part. The locking elements (for example, coils) are wrapped round or placed over a portion of a wheel nut. The interference/friction fit between the wheel nut and the clip or element prevents axial movement of the clip relative to the nut. The part serves as restraining means positively linking tangentially adjacent wheel nuts and thereby prevents relative rotation thereof.