Cole-Parmer Two-Hole Stoppers, Rubber

These two-hole black stoppers made with solid natural rubber stay pliable over a long period of time. Provide good tightness and adhesion, withstand laboratory conditions without hardening, and are ideal for use with nonaggressive or low concentration solutions. Each stopper has its size marked in raised figures. Low sulfur content. Withstand temperatures from –13 to 158°F (–25 to 70°C).