Re-Bich cooler (cooling tube) is one of the most common "Reflux Condenser".
It is mainly used in combination with other glass equipment when distillation or return (relax).
It is cooled out to the outside of the double tube structure, cooled, cooled down and condensed (liquefied).
Since the inner tube is a steering cylinder, it is a cooler that is often used in a slope (diagonal) because the condensed solution does not accumulate even if it is diagonally.