white polypropylene cap (15mm center hole), tan PTFE/silicone, thickness 3.2 mm, thread for 24-400, for use with 20 or 40 mL vial, pkg of 1000 ea. Expand. Hide. SU860006. white polypropylene cap (solid), tan PTFE/silicone (EPA Quality), thickness 3.2 mm, thread for 24-400, for use with 20 or 40mL vial, pkg of 100 ea.