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. Neoprene offers good resistance to oil and petroleum base solvents and excellent resistance to dilute acids. Known by the chemical name chloroprene, 60 durometer neoprene is made from 100% neoprene and is suited for various applications while giving users a gasket material with excellent weathering and ozone resistance.