"I have now purchased and fitted several hundred of the Tower male adapters and while they are cheap, the design and reliablility are very poor. This is simply because Tower have replaced the good old reliable screw thread on the backnuts with a stupid series of projections.
Any kind of pressure on the fittings after assembly and tightening causes the backnuts to give way and fall off. If they need replacement because one of the projections has broken and you have a long length of conduit wiring going through it causes a lot of extra work.
Please ask Tower to throw this stupid design in the bin and supply standard and proven threaded backnuts like other manufacturers."