15 New rubber stopper, Self healing Inoculation port, Injection ports 

Great for making your own span or liquid culture jar lids. 

Can be pressure sterilized.

20 mm, 12 mm diameter hole.

This design provides maximum sealing for vials with a blow-back glass finish, which is a small ridge on the interior of the vial’s neck. The snap-on stopper locks into the blow-back ridge, providing a tight seal and keeping the stopper from backing out.