Abstract: Control and cut-off device for media flowing to consumer apparatuses and flow back therefrom. For example, dosing equipment, ventilation assemblies, heating and cooling arrangments, among which also conditioning plants are classified. The valve is then made especially to be reliable also after a long period of service, to give a close control of a small quantities of medium, to be capable of admitting locking of the pre-setting and thereby to prevent unauthorized persons from making a resetting without difficulty and to admit cutting-off of the consumer apparatuses from the source of medium. The control and cut-off device according to the invention includes a valve housing, having two connection openings connection to a source of medium and two connection openings for connection to consumer devices and within the valve housing a rotation control and cut-off member to control and cut-off the flow of medium.