These stoppers fit serum vials with a 20 mm crimp neck finish. They were made for lyophylization (freeze drying vaccines). But they are also handy as general purpose stoppers.

 (sold out)

These stoppers fit glass serum vials with 20 mm necks and are the kind held in place with aluminum crimp bands.

They are Wheaton brand. They are lyophilization stoppers, which means they can be partly inserted, allowing air flow during freeeze drying, and then pressed home to make the seal. They are unlubricated.


  • Fit 20 mm finish vials
  • 20 mm outside diameter
  • 13 mm across the plug
  • Lyophilization
  • NOT Silicone lubricated
  • Grey butyl rubber


  • brand: Wheaton
  • size: 20mm
  • material: Butyl rubber

Condition: New. Not sterile.