Test tubes and culture tubes are made from machine drawn, uniform thickness, low expansion borosilicate glass tubing. The bottoms of these are with uniform thickness to withstand both mechanical and thermal shocks. The rims wherever provided, are strong. Test-tubes without rim (Culture tubes) have heavy fire-polished ends which are resistant to mechanical shocks of daily use. Culture tubes are good for cell growth. The caps and washers provided on Screw cap Culture tubes withstand repeated autoclaving.
