Septa for 8-425 screw thread caps are constructed of PTFE, PTFE/rubber, or PTFE/silicone to suit a variety of HPLC, GC and IC applications.

• PTFE Disk septa are chemically inert
• PFTE red rubber septa are economical for many GC applications
• PTFE/silicone septa are most popular for HPLC and IC applications
• Pre-slit septa are easier to pierce with thin gauge needles