Please note this is a 450mm diamond dome sunpipe for a flat roof and comes complete with a galvanised flashing plate and fixings. Can be installed on felt, asphalt, membranes such as EPDM and gravel. A special extended flashing may be required if being installed onto a green roof. Properties Diameter: 450mm/18".Length: 610mm.Area of lighting: 22m2.uValue: 2.18 W/m2.Flashing: Galvanised steel with ABS collar.Ceiling opening: 470mm. Kit contents 1x polycarbonate diamond dome.1x galvanised flashing plate and ABS collar.1x 610mm plain end pipe.1x plywood backing plate/template.1x 250mm ceiling extension.1x 3-piece ceiling diffuser.Fixings, includes silicone sealant, screws, sealed rivets, neoprene washers, brushed nylon condensation seal, aluminium tape and universal fitting instructions. Materials Diamond dome: 4mm UV Stabilised polycarbonate.Sunpipe: super silver mirror finish aluminium.Upstand: galvanised steel. The sunpipe natural daylight system directs sunlight into a room from roof level. The sunpipe collects daylight using a patented diamond dome, using a silverised PVD coated mirror-finished aluminium tube to transfer light to a room, with a ceiling diffuser evenly distributing the light around the room. Sunpipes are suited to almost any application and have been installed anywhere from residential bedrooms to the Olympic handball arena in London.