For use with PolyFit/PolyPlumb Polybutylene pipe. – Material: Stainless Steel. Note: Must be used with Polybutylene pipe. Guarantee: Polypipe guarantees for 25 years against defects in materials or manufacture of the PolyFit/PolyPlumb hot and cold water supply and heating systems from the date purchased. This guarantee only applies if the products are installed in accordance with the manufacturers recommendations and are used in a normal domestic operation.