Slim & Strong. Supplied With bolts. High Tensile AluminiumSWL: 300 kg Tube Diameters: 48 to 51mm Width: 30mm Fixings: M12 Hole Weight: 0.32 kg. The Slimline Lightweight Half Coupler is the Basis of the range of Lightweight Doughty Clamps. This Clamp has a slotted base to captivate an M12 Nut or Bolt enabling users to create fixings suited to their own individual requirements. Ideally suited to hanging small to medium sized luminaries. Manufactured from high tensile Aluminium Extrusion.. doughty fixing-doughty trussing