PTFE Sealing rings for glass joints

Greaseless joints extra tight and extra clean. An alternative to common PTFE-joint sleeves and PTFE stoppers. Air leakage < 10^-8 to 10^-6 mbar * l / s (high vacuum and overpressure). Solvent leakage from jars < 0.1 to 0.03 mg / day. Rings match KECK plastic joint clamps, do not deform and are reuseable.