Inexpensive, tapered stopper provides for a tight, leak-proof fit while the top ring permits the stopper to be easily removed. Stoppers are made of yellow Polyethylene

Sleeve type stoppers with a hollow plugs and sleeve extensions that folds down over the neck of a vessel, tubing, etc. The diaphragm can be punctured with a syringe needle, re-sealing after the needle is withdrawn. Available in either RED or WHITE rubber.