This EVAC Aluminum Metal Seal ISO63 LF63 flange is for converting Elastomer rubber seals to UHV aluminum metal seals. This allows for a lower vacuum compared to elastomer rubber seals. Other benefits include: reduced outgassing, no permeation , no hydrocarbons, and resistance to radiation and higher heat. The resultant UHV seal has a helium leak rate of less than 1 X 10 -11 standard cc/sec. They can also be baked repeatedly to 150°C (302°F). The ISO double or single claw clamps and an aluminum knife edge seal form the UHV vacuum seal between the connecting ISO LF flanges. This EVAC metal seal is made of aluminum. This is a ISO63 LF63 aluminum metal knife edge seal only.