9mm Blue Plastic Screw Caps is suitable for: 9mm Short Thread HPLC Vials Caps Material: polypropylene, size: 11.5*6mm, inner diameter: 9mm, with 6mm Centre Hole or Closed-Top Color: usually blue, other colors are also provided, such as red, black, yellow, etc The Septa are PTFE / silicone, size: 9*1mm, the sapta could be pre-slit