Abstract: This invention relates to a method of connecting precast components to each other. More precisely it is a coupling system for joining structural concrete components for use in the construction industry. This invention is a coupling of and for precast concrete components, the precast concrete members rely on being cast with a precisely formed monolithic “maile or femaile” (inverse coupling) shape that slips together easily with the mating component. When these components are joined they create an interlocking assembly (connection zone). In the connection zone, concrete grout is placed before the components are joined, as they are connected gravity and the components weight seat the coupling in compression. When the grout cures a permanent structural, monolithic coupling is formed.