Round Bottom Flask - 500mL Still Head with Thermometer Support Liebig Condenser - 300mm Receiver Adapter 3 x Joint Clip - 19/26 All components needed to perform basic distillation procedures are included in one convenient set. Made from high-quality Borosilicate 3.3 glass with 19/26 joint sizes. Autoclavable, with superior chemical durability. Low temperature gradient - can withstand high temperatures & thermal shocks. Eisco Labs Borosilicate glass has the following heat tolerances: Strain Point 515°C | Annealing Point 565°C | Softening Point 820°C.