This standard schlenk flask is a round bottom, pear-shaped flask with a ground glass joint and a side arm, which has a 2mm glass stopcock to control the flask's exposure to a vacuum manifold for a schlenk line. The glass out joint at Top is used to add material in the flask and can be stopped by a ground glass stopper. When the flask is connected with a vacuum manifold under a positive pressure of inert gas, the stopper can be replaced with other apparatus, for example a reflux condenser. Laboy glass flasks are heavy wall designed, made by hand-blowing to ensure uniform wall thickness, made of high-quality borosilicate glass and annealed at 800 degree Celsius, can be heated directly in an open flame and can withstand typical laboratory thermal variations in Chemistry processes like heating and cooling.