PYREX Reusable Phenolic GPI 15-415 Screw Cap w PTFE Liner 9998-15
These reusable PYREX Caps have GPI 15-415 threads and are provided with a glued-in rubber liner over which is firmly bonded a Polytetrafluorethylene (PTFE) interface to provide a highly inert sealing face. Warning: Caps should be loose to avoid liners being pulled out by the vacuum created when cooling