The 100762063 Viton O-Ring is designed for use with size NW630 ISO-BF centering ring assemblies. This 2-474 size O-ring is made of black Viton compound V747-75 and is rated for up to 150 deg. C bakeout temperature. This Series 76 accessory offers enhanced chemical resistance and lasts longer than similar Buna-N O-rings and can be used as a spare or replacement O-ring.