This European Standard specifies, for right angle couplers, swivel couplers, sleeve couplers and parallel couplers working by friction: - materials; - design requirements; - strength classes with different structural parameters including values for resistance and stiffness; - test procedures; - assessment; and gives - recommendations for ongoing production control. For testing, screw couplers are tightened to a torque of 50 Nm and wedge couplers are tightened with a 500 g hammer until the jarring blow.