Made of bromobutyl rubber. Can be used with all DURAN® laboratory glass bottles with a GL 45 thread. Can additionally be secured with a screw cap with hole (recommended only for non-pressurised applications). Low permeability for air, gases and moisture. Top side has seven numbered semi-circular depressions to be pierced with tubes, good self-sealing characteristics when pierced repeatedly. Temperature stable from -50 to +121 °C.

Pack of 10