The VILPE Chimney pass-through is designed for round prefabricated insulated metal chimneys and it is available in two sizes. The Chimney pass-through No. 1 is designed for round chimneys of diameter 200–265 mm, and the Chimney pass-through No. 2 is designed for chimneys of diameter 280–380 mm. A rubber gasket and a fastener are provided for attachment to the plastic Chimney Pass-Through plate. The Chimney Underlay Seal comprising two plastic parts, a rubber seal and butyl tape, prevents the flow of water into the hole made in the underlay, thereby ensuring that it remains watertight. The product may be used on tiled and sheet metal roofs with the three-part VILPE Flashing Set. This is not required for felt roofs. VILPE Chimney Pass-Throughs and Underlay Seals have been tested for fire safety and certified by the VTT Technical Research Centre of Finland.