The Claisen adapter can be placed on top of a round bottom flask to convert one opening into two, For example, attach one upper joint of the Claisen adapter to a condenser and one to an additional funnel or accept a thermometer adapter for temperature measurements in a distillation apparatus; This Claisen adapter has two upper outer joint to attach any lab glasswarer with inner joints, and a lower inner joint to entry into a boiling flask with outer joint. The sizes of the three joints are the same 24/40. Laboy Glass Claisen adapter is 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.