Merchant couplings are machined from rolled steel, and these are the only fittings we sell that are made from the same industrial steel as our pipes. They are manufactured to the same specifications as all our other fittings, with the added benefit of steel. Hydrostatically tested, these merchant couplings are ideal for decor as well as plumbing applications in air, gas, and liquid propane. Each coupling joins two pipes of the same diameter for a strong and sturdy extension. You will know PIPE DECOR parts and accessories when you hold them—beauty and beast, strength and style. These are real industrial fittings for your decorations and designs. Accept no substitutes. Extra pieces and accessories are available for your custom projects and expansions. Plug and play as desired. Perfect for any DIY project, these fittings complement a variety of looks and aesthetics, including steampunk lighting, industrial, factory, French country farmhouse, vintage, retro, reclamation, DIY customized, modern, and more. We recommend cleaning and sealing each fitting before use. IPS threads offer compatibility with other project materials such as lamp parts, valves, and more, and they are compatible with any pipes, fittings, and PIPE DECOR furniture kits of the same diameter.