Aluflow 12.5mm Gutter Bracket Stainless Safety Screw 50 Pack Lean To With Open Sides (Front Posts) 1 x Wall Upstand and 1 x Gable Side It is recommended to use LENGTH:50m It is recommended to use a Top Wall Flashing to seal the back of your roof and provide better waterproofing Axgard Clear 12mm sheet is the thickest option that we manufacture and it goes without saying that it is the strongest and most rigid solution of the entire Axgard range They are used to prevent any movement of the Aluflow aluminium gutter in the unlikely event there is some vertical movement within the Brackets as indicated in the fitting instructions