"Moulded" in this context usually means that the pipe has a specific shape, which may be different from the traditional cylindrical pipe shape. Basically, these pipes have a non-cylindrical shape, often with bends or angles. This distinguishes them from standard cylindrical pipes, which have a uniform diameter along their entire length.
Custom moulded pipes can be made from a variety of materials, including metals such as steel, aluminium and stainless steel, or plastics, and can be modified in a variety of ways including by bending, welding or pressing, to achieve the desired pipe shape and dimensions.
