Part of the GL (glass laboratory) thread standard, the GL38 thread has become essential for packaging solvents in laboratory settings. It's commonly found on amber 4-liter glass bottles from chemical suppliers and is valued for its secure fit with airtight safety caps, ensuring the safe storage of volatile chemicals.

While the GL38 thread technically features a 38-430 thread finish, its slightly different height makes it incompatible with the 38-430 threads on plastic bottles. Specifically designed for glass containers, GL38 threads are a trusted choice for solvents, reagents, and other chemicals in both laboratory and industrial applications.

All Lab Lids safety caps for solvent extraction include ported inserts—threaded ports designed for secure tubing connections.

For integrated evaporation control, choose caps with built-in check valves that regulate airflow in a single direction. These valves allow air into the bottle to prevent vacuum buildup while solvents are pumped to the instrument.

Check valves are available in three material options based on chemical compatibility needs. Each seal material is color-coded by the particulate filter at the center of the cap:

• FFKM for nearly universal compatibility (yellow filter color)

• FKM (green filter) and EPDM (blue filter) for cost-effective alternatives with a narrower compatibility range.