A simple, all PTFE septum injector. Allows direct, on-column injection to the center of the filter disc at top of column without stopping the solvent flow through the 1/4"-28 female side thread (with or without helicoil). Locknut design provides leaktight seal without o-rings. You can order the 5/16"-28 septum cap separately from the body. Use our 12689 tubing for the side thread addition of solvents.