John Guest push-fit acetal double check valve provides protection from the reversal of flow or back siphonage against Fluid Category 3 risks. he low headloss design, is suitable for potable liquids , foodstuffs, intermittent hot water (up to 50oC max and in accordance with The British Beer and Pub Association Code of Practice), water treatment and purification applications. Fast and simple to install, John Guest valves create an instant push-fit connection and leak tight seal without the need for tools, hot works or sealing agents. The unique collet locking design firmly and securely holds the pipe in place without deforming the pipe or restricting flow. John Guest push-fit valves are corrosion resistant and fully demountable, improving system performance and reducing system downtime during maintenance. All John Guest fittings are manufactured and assembled in the UK.