For use with plain thermometers, pipets, syringes or other small items with an OD from 2 to 17mm. A vacuum-tight seal is created with the open top compression cap and FKM o-ring to allow adjustable immersion of thermometers. Cap is suitable for use to 150°C. To use it as a septum port, just replace the o-ring with a PTFE-lined septum. Supplied with one FKM o-ring and one 410119 cap. Ref: ASTM Method D1744.