Stopper Stopper Size 6.5 Neck Size 29 mm Screw Closure Size 29mm Bottom Diameter 27 mm Top Diameter 34 mm Overall Height 25 mm Material Natural Rubber Product Type Stopper Color Black Autoclavable Yes Number of Holes 1 Standards Not Applicable Special Features Low Sulfur Content Withstand Temperatures From - 25 to 70 Degrees C (-13 to 158 Degrees F) Resists Abrasion and Water For Labware Type Erlenmeyer Flasks Test Tubes Liner Material Natural Rubber Hole Diameter 5 mm