Rubber Stoppers - Size 4, One-Hole

For Test Tube 25 x 150mm
Top Diameter: 26 mm
Bottom Diameter: 20 mm
Length: 25 mm
Approximate Number Per lb: 28
Developed for demanding laboratory work. Soft, pliable, resilient, low in free sulfur, resistant to chemical attack. Made of black or blue rubber. Size numbers are molded into the top. 

NOTE: Bottom of stopper diameter must be smaller than test tube diameter.