White Flip Off Tear Off Vial Seals, West, Pk 100. For use on serum vials with a 13mm diameter hole opening and 20mm rim to rim diameter. The plastic lid will flip off and expose the underlying stopper for use with a syringe - or - a metal pull tab underneath the plastic lid can be pulled down to completely remove the aluminum seal and stopper (sold separately). This will allow contents of the vial to be poured out.
Routinely used when packaging media broth for USP797 testing (Trypticase Soy Broth, etc).