Blue polypropylene short screw-thread cap, 6mm center hole, 9mm diameter, with pre-slit red PTFE/white silicone septa, 100/pk, CV1815. Labware Tubes, Caps, Vials, and Racks Caps and Closures Items 1 - 60 of 337 Screw Cap MER 9SP30052A 9-425, Blue ribbed screw cap, Red PTFE/White Silicone Septa, Pre-slit $20.99 / PK Available: 1596 PK.