United Scientific Supplies RST16-S Rubber Stoppers, Solid, #16

These black stoppers are made of solid natural rubber that stays pliable over a long period of time. Ideal for use with non-aggressive or concentrated solutions. Low sulfur content. Withstand temperatures from -25 to 70°C (-13 to 158°F). Each stopper has its size marked in raised figures. Sold as one-pound bags.