100PK Test Tubes, 50mL, 24x150mm - Rimmed - Light Wall, 1.2mm Thick - Borosilicate 3.3 Glass

This 100-pack contains heavy duty borosilicate 3.3 glass test tubes with a 50mL (1.7oz) capacity and uniform 1.2mm walls. Each tube measures 5.9 inches (150mm) tall with an outer diameter of 0.95 inches (24mm) and an inner diameter of 22.8mm. The tubes accept stoppers with a bottom diameter of 20 to 21mm and a top diameter of 24 to 26mm. These tubes run the same 150mm height as the 25mL version but nearly a quarter inch wider, so the 24mm bore should be checked against existing racks. The rims are fire polished into a bead rather than cut, which rounds the glass edge under heat and removes the microscopic flaws where cracking begins. The resulting rim resists chipping through repeated racking and washing and gives a stopper a defined seat. Uniform wall thickness prevents thermal stress concentrating at a thin point. Borosilicate 3.3 glass withstands direct flame, high temperatures, and thermal shock, and the tubes are autoclavable for sterilization and reuse.