Malmo Steels Pvt. Ltd. Produces Gravlock Girder Couplers. Malmo Steels Pvt. Ltd. Is into business of producing scaffolding products. This is Gravlock Girder Couplers is designed to connect scaffold tube to beam or girder flange. A pair of gravlock girder couplers must always be used and it weighs up to 1.30 kg.