Fireplace bellows are built with a triangular design and function as a single air pump tool. Most fireplace bellows consist of wood-carved handles with a leather expandable middle. They consist of an air chamber and a valve (or nozzle.) The air chamber has an accordion like design which allows it flexibility to grow and contract with use. Bellows have two handles which, when pulled, force the chamber to "inhale," drawing air inside itself for storage. When the handles are pushed downward, the air chamber forces the air out through the nozzle. Air blows out of the nozzle and onto a small fire or smoldering log to stoke the flames. As the handles are repeatedly lifted and pushed, the air is drawn in and pushed out, allowing for regular puffs of air.
There are two categories of bellows: the common single-acting piston bellow and the double-acting. The single bellow functions by bringing air in and expelling the air in two different and distinct motions of the handles. The double-acting piston bellows allow for air to be blown out in both strokes of the bellows' handles. They are considered stronger and deliver more air than the tradition single piston bellows.
If taken care of by cleaning and oiling of the air chamber's materials, fireplace bellows can last for decades. Some antiques are centuries old and still in working condition. However, if the metal has been left to rust and the wood to rot, the fireplace bellow is nothing more than a poorly conditioned antique.