Manufactured from 5.1 expansion borosilicate glass conforming to USP Type I and ASTM E438, Type I, Class B requirements, these threaded culture tubes are suitable for a variety of lab settings.

• Each tube is heat-treated at temperatures exceeding 500° C and immediately packed in a shrink-wrapped cardboard tray, 250 tubes per tray.
• This process avoids contamination and increases the strength and durability of the glass.
• Dimensional tolerances are strictly controlled for a uniform shape, including rounded bottoms and polished tops with smooth edges.
• Each tube has a chevron-shaped white enamel marking spot.
• Threaded necks accept a phenolic screw cap, not included.
• Available in six sizes, from 8 ml to 33 ml. Type I, Class B 5.1 expansion borosilicate glass.
• Heat-treated and securely packed to avoid contamination and increase strength.
• Chevron-shaped marking spot for easy orientation reference.