Helical flexible couplings can be utilised in couplings, incorporated into a single part eliminating the cost involved in purchasing and assembling two or more parts. It also enables customer end-attachments, such as tangs, clamps, flanges and threaded ends to be intergrated into a single, multi-functional component. These couplings find applications in petrochemicals, instrumentation, encoders, tacho-generators, lead screws, ball screws, air cooling units, pumps, machine tools cnc machines aerospace and aircraft industries, duplicators, stepping motors feedback devices.