Spigot Plates product details:
Spigot plates are used to attach ducting to flat surfaces. Spigot plates are available in 100mm, 125mm, 150mm, 200mm, 250mm and 315mm sizes to suit all the sizes of ducting we sell.
Using spigot plates couldn't be easier all you do is place the plate on the surface you're looking to extract through and mark out the hole size. Use a saw to cut out the hole and then drill some holes through the flange and screw it onto the surface. The easiest way to use spigot plates is with wood, if you need to mount spigots on brickwork the best approach is to make a cover out of thin plywood that would go over the hole in the brickwork.