Pressfit Gas fittings are manufactured from copper or copper alloy and are designed specifically for use on internal and external, above ground 2nd and 3rd family gas installation pipework. BSI Kitemark (BS 8537:2010) and GASTEC approved. Manufactured by a BS EN ISO 9001:2000 registered company. for identification fittings have yellow/tan NBR O-rings and "Gas" marked in a yellow block on the fitting body. Working pressure range : 1 bar (internal use), 5 bar (external use) at -20°C to 70°C.XPress Fittings provide electrical continuity when pressed/installed with copper tube to BS EN 1057 R250/R290. Pressfit Fittings should not be painted or come into contact with cleaning products, paint, grease, flux, mineral oil, adhesive or other solvent based materials during installation, lagging or after installation.