It are designed for precise laboratory applications. Manufactured from high-quality Pyrex borosilicate glass, these tubes offer exceptional resistance to thermal shock and chemical corrosion. Each tube measures 16 mm in diameter and 160 mm in height, with a nominal capacity of 20 ml. The GL 15 thread ensures compatibility with the included phenolic screw cap, which features an inert PTFE-lined rubber disc, providing a secure and leak-proof closure. The cap can withstand repeated dry heat and steam sterilization cycles (121°C for 2 hours).