This is the single spiral groove of flexible coupling made by aluminum. This design utilizes a single piece of material and becomes flexible by removal of material along a spiral path resulting in a curved flexible beam of helical shape.Changes to the lead of the helical beam provide changes to misalignment capabilities as well as other performance characteristics such as torque capacity and torsional stiffness. It is even possible to have multiple starts within the same helix.
Made from aluminum.
Compatible with most 4mm shaft especially D shaft.