Product Description 25mm Barbed Plastic Non Return Valve Used in-line, this product does not allow water to flow back towards the water feed after the supply has been turned off. Saves having to charge the pipe lines of water at start up time. PVC-U – Unplasticised Polyvinylchloride Injection Moulded To Fit LDPE pipe with 25mm Outer diameter, 21mm Inner Diameter Click for Product Brochure