Septa for 8mm Screw-Thread Vials, Restek Supplier: RESTEK CORP Septa for Restek screw caps are available for use with vials with 8 mm wide openings. Screw-thread vial compatibility Economical Red PTFE/silicone Septa for convenient compatible use with all 2.0 ml, 8 mm screw-thread vials. Order Now ORDER Q and A Generate Barcodes