Abstract: The system comprises an at least partially threaded male member of plastics material including one or more first discontinuities, such as a bolt with a plurality of substantially rigid webs between portions of a helical rib thereon, and an at least partially threaded female member of plastics material including one or more second discontinuities, such as a nut with a resiliently deflectable tongue whose free end is located beyond one end of the helical rib therein.Threaded advance of the male member, relative to the female member, causes deflection and resilient return of the first and/or second discontinuities as they pass one another, such as deflection and resilient return of the tongue as it passes each of the webs, to give an audible click and an abrupt change in drive torque or other tangible indication of the extent of said threaded advance.

Abstract: A cable clamp which is a one piece plastics moulding, grips by two pairs of wings, and independently resists both pushing and pulling of the cable because the two pairs incline in opposite directions. The cable is slid along the gripping edges of the wings when being applied to the clamp, and the wings do not bend or crimp the cable. The clamp can have an integral closeable lid and a fastener for anchoring to an apertured support.