16mm X 5m Green Rainwater Water Pex B Pipe is a single layer pipe suitable for rainwater systems. 25 year warranty is conditional upon installing Tradespersons having the appropriate regulatory licenses and having been trained and certified by the Couta Group in the correct installation techniques for the systems and installed in accordance with National Gas and Water Plumbing codes such as AS3500 and AS5601. Warranty is void where the installer does not use Couta Group fittings and pipe together.