Klober Large Slate Vent (Base Only) made from rigid PVC with a matt, slate grey finish that blends well with slate roofs & suitable for use with either natural slate or man-made slate, this vent can be used on roofs with a pitch of over twenty degrees & with slates sized six hundred by three hundred millimetres or five hundred by two hundred & fifty millimetres. Cleverly designed to deny access to birds & large insects, the Klober Large Slate Vent (Base Only) comes with a pre-installed downpipe that provides an unobstructed ventilation route through into the roof space to reduce wind noise. It is fully compliant with Building Regulations & all the relevant British Standards. To ensure a perfect fit that is flush with the slate course, the Klober Large Slate Vent (Base Only) is positioned as a standard slate tile with a hole cut in the underlay to accommodate the downpipe with an underlay sealant used to ensure the integrity of the underlay following the installation of the vent. Product features & benefits: Low profile design makes it unobtrusive on the roof line Fits perfectly with adjacent slates Slate grey cap blends in with most man-made or natural slates Built-in downpipe to ensure direct ventilation path into the roof space Fully wind tunnel tested Adaptor & flexipipe available forsoil ventilation or mechanical extraction Prevents entry of birds & large insects Dimensions: 600mm long x 300mm wide x 85mm deep (excluding downpipe)