bmotiontechKF50 Stainless steel vacuum Centering Ring with O-ring = Viton (5pcs pack) KF-50 NW-50 Vacuum Stainless steel centering ring with Viton O-ringKF50 Centering ring is made of stainless steel 304O-ring is made of viton material.Viton Working temperature -10F to 400F （-20C to 200C）Good chemical resistanceCentering Ring KF-50 Vacuum Fittings, ISO-KF Flange Size NW-50, Stainless Steel & VitonThese KF-50 Centering Ring vacuum fittings follow ISO-KF standards and have a flange size of NW-50.They are commonly used to build foreline vacuum plumbing and process systems.They are often called quick flange fittings because they are quick to assemble.A circumferential clamp and centering ring form the vacuum seal between the connecting flanges (please see top right figure - click to enlarge). The centering ring contains a rubber elastomer o-ring. The standard sizes for quick flange fittings are KF-10, KF-16, KF-25, KF-40, and KF-50 with flange sizes NW-10, NW-16, NW-25, NW-40, and NW-50, respectively.They are made of corrosive resistant stainless steel with Viton O-Ring.Viton is well known for its excellent resistance to heat (400F/200C) and to aggressive fuels and chemicals. Viton is a registered trademark of DuPont Performance Elastomers.We only accept PayPal on eCRATER, this means you can rest assured your order will be with you ASAP after your purchase. For your security we only despatch your order to the address you provide us via PayPal.As soon as you pay, eCRATER & PayPal will email you to let you know it's been received and as soon as we've shipped your order, we'll let you know by email that it has been despatched and the tracking number if applicable. "We want you to be 100% happy with your purchase and offer a 14 day "no quibble" guarantee"If you change your mind, or the purchase is not suitable, you may notify us to cancel the contract within 14 days after the day of receipt of item(s) and you have a duty to take reasonable care of the item(s) until we receive the item(s) back. Return posting costs will be at your expense.Any Questions?Please check this listing page carefully as the answer is usually there. If not, let us know and we'll try our hardest to reply within one working day. "" ( ) "" ( ) "" ( ) "" ( ) "" ( ) 3.1210525804bmotiontech32174841946230-04-2017 15:40:3330-04-2017 15:40:33On Apr-30-17 at 07:41:09 PDT, seller added the following information: