Flask Only, 3,000mL Single Neck Heavy Wall Wide Mouth Recovery Flask, GL80. Heavy wall, wide mouth flask with a GL80 glass thread and a 24/40 connecting adapter. Flasks have a heavy wall for vacuum applications and are balanced to prevent run-out during rotation. Unique design makes it easier to handle highly viscous liquids, powders, and solids. The large opening permits trouble-free emptying and cleaning and easy access of products with a spatula or policeman. The flask contour is excellent for controlled evaporation of foaming solvents during rotary evaporation.