Please note, this CemVent does not come with slate included.CemVent is probably one of the most versatile Natural Slate Ventilators available on the market today. CemVent will match perfectly with any slate simply by using a piece of the same slate, cut on site and fitted into the bottom section. No unsightly plastic mushrooms to spoil the roof, just a discreet grill, coloured to blend into the finished roof. CemVent can be used for the termination of soil vents or extractor fans (with optional flexi pipe) or to simply ventilate the roof void. Developed by one of Europe's foremost producers of roof ventilation products, CemVent is manufactured from UV stabilised material, using design technology developed proven and tested during more than 30 years of experience in this specialised field. A perfect match every timeSimple to install Economically priced Weight: 665gm Material: High impact Polystyrene, UV stabilised Pitch: Recommended minimum roof pitch 30 degrees Headlap: 100mm Capacity: 10,000mm2 free air flow Outlet: 110mm