"An all steel fixing for light weight aggregate blocks. Ideal for fixing in areas such as fire escape routes where regulations restrict the use of plastic anchors or plugs.External teeth expand and grip into the material, giving high load bearing strengthDesigned specifically for use with wood and chipboard screws, the internal ribs interlock with the screw's thread to provide a secure fixingIncreased installation safetyWide range of applicationsAll steel, non-flammable fixing conforming to BS 7671 standard's 18th edition, which requires wiring systems to be supported by materials which are unlikely to prematurely collapse in the event of a fire. ""Diameter mm: 8.0Length mm: 60Material: Carbon SteelFinish: Zinc & YellowDrill Hole Dia. mm: N/AMin Drill Hole Depth mm: N/ATo Fit Screw Dia. mm: 5.0: 6.0To Fit Screw Gauge imp.: 10: 12."