High Tensile Aluminium. Slotted Base to Captivate an M8 or M10 Nut or Bolt. Black or Silver FinishSWL: 100Kg Fixing Hole: M10. The Atom half coupler clamp has a slotted base to captivate an M8 or M10 Nut or Bolt enabling users to create fixings suited to their own individual requirements.. clamp-doughty clamp-half coupler-truss clamp-lighting clamp