An adjustable hydrocephalus valve for equalising the pressure of the cerebrospinal fluid in the skull of a hydrocephalus patient, wherein the valve can be implanted in the patient and is preferably provided with a hose line which can also be implanted and via which excess cerebrospinal fluid can be withdrawn from the skull of the patient and drained into the superior vena cava or into the abdominal cavity, wherein the valve pressure is determined by a spring and wherein the spring is adjusted via an adjusting mechanism so that the spring is tensioned or relieved, wherein the adjustment mechanism of the valve includes a pivotable or rotatable pivot member/rotor arranged in the valve, which is provided with magnets and is movable from the outside by pivoting or rotating an adjustment device, which in turn is provided with magnets, wherein the valve is provided with a locking device for the pivot member/rotor, so that the pivot member/rotor can be locked between two adjustment processes, and wherein the locking is effected by frictional engagement and/or by a toothing between the pivot member/rotor and the housing, and wherein the rotatable or pivotable pivot member/rotor can be moved in the axial direction for cancelling the frictional engagement or for cancelling the engagement of the teeth by pressing in the valve cover in the axial direction, wherein the unlocking movement takes place against a spring force which causes the frictional engagement or the tooth engagement during locking, wherein the valve is provided with a spring, which is independent of a housing deformation, for producing the frictional engagement or the tooth engagement, wherein the spring is provided between the pivot member/rotor and the housing base, characterised in that the valve cover is formed by a spring leaf which has a bump before unlocking which can be abruptly brought into an opposite bump by pressing it in with the adjusting device. wherein the adjustment mechanism of the valve includes a pivotable or rotatable pivot member/rotor arranged in the valve, which is provided with magnets and is movable from the outside by pivoting or rotating an adjustment device, which in turn is provided with magnets, wherein the valve is provided with a locking device for the pivot member/rotor, so that the pivot member/rotor can be locked between two adjustment processes, and wherein the locking is effected by frictional engagement and/or by a toothing between the pivot member/rotor and the housing, and wherein the rotatable or pivotable pivot member/rotor can be moved in the axial direction for cancelling the frictional engagement or for cancelling the engagement of the teeth by pressing in the valve cover in the axial direction, wherein the unlocking movement takes place against a spring force which causes the frictional engagement or the tooth engagement during locking, wherein the valve is provided with a spring, which is independent of a housing deformation, for producing the frictional engagement or the tooth engagement, wherein the spring is provided between the pivot member/rotor and the housing base, characterised in that the valve cover is formed by a spring leaf which has a bump before unlocking which can be abruptly brought into an opposite bump by pressing it in with the adjusting device.