Large Stopper with Single Hole

Large Neoprene Stopper with One Hole - Perfect for Flasks, Beakers, and Bottles The Large Neoprene Stopper with One Hole is a durable laboratory stopper designed for use in homeschool and classroom chemistry labs. Made from flexible neoprene, this stopper provides a secure seal while accommodating glass or plastic tubing through its pre-drilled center hole. Its tapered design allows for a snug fit in compatible flasks and bottles, making it ideal for experiments involving gas transfer, filtration setups, or closed-system reactions. The single hole allows easy insertion of thermometers or delivery tubes while maintaining a controlled environment inside the vessel. Product Specifications: Neoprene construction Single pre-drilled center hole 21 mm diameter at base 24 mm diameter at top 28 mm height A practical lab accessory for structured chemistry curriculum, this 10-pack of one-hole stoppers supports hands-on experimentation in homeschool programs, co-ops, and classr