Thermo Scientific™ 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. Choose from Thermo Scientific™, Thermo Scientific™ National™, and Thermo Scientific™ Chromacol™ brands. This product (s) resides on a Fisher Scientific GSA or VA contract.