Manually controlled. Made of borosilicate glass 3.3, DURAN®, with ground joint socket NS 29 / 32 for a recirculating condenser, ground joint cone NS 29 / 32 for a distilling column, ground joint socket NS 14 / 23 for a thermometer with ground joint (or similar) and side PTFE valve (adjustable) for setting the return flow, with ground joint cone NS 14 / 23 for a collecting flask. Manually controlled. Made of borosilicate glass 3.3, DURAN®, with ground joint socket NS 29 / 32 for a recirculating condenser, ground joint cone NS 29 / 32 for a distilling column, ground joint socket NS 14 / 23 for a thermometer with ground joint (or similar) and side PTFE valve (adjustable) for setting the return flow, with ground joint cone NS 14 / 23 for a collecting flask.