Push Fit Plumbing 15mm Isolation Valve Red/Blue Whitespeed, reversible Red / Blue disc ( always use lubricant & pipe inserts/stiffeners ) BS EN ISO 9002 & Conforms To BS7291 part 1 & 2. For Hot & Cold & Central Heating Systems So These PB Fittings Will Not Be Affected By Anti Corrosion Properties ie Sentinal & Furnox. Can Also Be Used on Copper When Adapting To Central Heating Systems .