Bell jar and cylinder vacuum chambers typically use L gaskets to create a seal. The L gasket, named for its "L" shaped cross section, creates a tight seal between two mating surfaces. The seal helps prevent leakage by filling in any surface irregularities. Our metal band clamps can be used to secure or hold a L gasket in place. You may also slightly lubricate the L gaskets with silicone vacuum grease to improve the sealing capability. Fits 6" OD vacuum chambers. Specifications Profile Type: Flat Dimensions: 6" OD Material: Viton All prices are in US$. Website pricing is good only for the USA and Canada. Please call for International pricing.