Abstract: The invention provides a prefabricated volumetric construction module having connection mechanism for securing to other similar modules. A prefabricated volumetric construction module includes a self-supporting structure and pairs of corner castings arranged at least at the corners of the structure. During building construction, the modules are assembled and secured together using connection rods and interlocking plates to provide vertical securement between vertically adjoining modules and horizontal securement between horizontally adjoining modules.