These PYREX® borosilicate glass melting point tubes are cylindrical with a round bottom, wide mouth and beaded rim.

Tubes have a modified design to increase the rate of circulation.

The unique configuration of the Thiele-Dennis tube is designed to create continuous flow when heated, so no stirring or shaking is required. Instead, convection currents created by the heat do the stirring for you. Tube diameter is 25 mm, and tube length is 165 mm.