At Leadworx we have a range of stock items but we also make orders to suit individual requirements. Here we have a trio of custom order slates on their way to a customer, two 10″ (255 mm) and one 12″ (305 mm).
Where a pipe or flue penetrates a roof it is necessary to provide a permanent solution to weather proof the hole created. Lead slates are the traditional product used to weather pipes as they pass through a roof as they can be formed into any size outlet and easily worked to fit with tiles, slates and many flat roofing materials. https://www.leadworx.com/ie/product-category/lead-slates/