Once you’ve fitted a Chimney Sheep in your chimney you should notice a massive reduction in cold draughts in your home. However cold air has a knack of sneaking in through the tiniest of gaps, which can be hard to locate. The Smoke Pencil is an ingenious gadget for pinpointing air leaks and tracking down hard-to-find gaps. When the trigger is pressed, a plume of smoke-like substance is released. This is actually generated from a harmless glycerine-like fluid, giving off a slightly sweet smell. When the trigger is released, the “smoke” stops, making it highly controllable. The Smoke Pencil Pro kit comes with attachments that enable a very fine stream of smoke to be created which means the tiniest of air leaks can be pinpointed.