The 100314005 Viton O-Ring is designed for use with size NW40 ISO-KF centering ring assemblies. This 2-326 size O-ring is made of black Viton compound V747-75 and is rated for up to 150 deg. C bakeout temperature. This Series 31 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.