Ring gaskets are a flat sealing element, consisting of an inner and outer diameter sized to fit a flange's bore and bolt circle. Ring gaskets sit inside the flange's bolt circle. ASME B16.21 and ASME B16.47 govern the dimensions of ring gaskets for standard and large diameter pipe flanges. Teadit NA 1076 sheet is a good all purpose sheet that is specifically formulated to handle a broad range of refrigerants. In addition, 1076 is suitable for services handling water, saturated steam, oils, fuels, mild acids and alkalies. NA 1076 is a compressed fiber sheet gasket material produced from a combination of aramid and other synthetic fibers and bonded with neoprene rubber (CR). It is manufactured through the hot calender process under rigorous quality control standards that are registered under ISO-9001 certification.