Pre-insulated fittings and spools are used in conjunction with pre-insulated pipes to create a complete piping system for the transport of hot liquids or gases. Fittings are used to connect two or more pipes together, while spools are used to connect a pipe to a piece of equipment or a valve.

Pre-insulated fittings are typically made from the same materials as the pre-insulated pipes they are used with, including a steel or iron inner pipe, insulation material, and an outer casing. The insulation material helps to keep heat inside the fitting, while the outer casing provides protection from damage. Pre-insulated fittings are available in a variety of sizes and configurations to suit different piping systems and applications.