Aluminium winding tube couplings for the RPR100-4 PowerRoller with weight compensation (GC). The coupling is needed for mounting the lifting cord of the weight compensation and is mounted on one side of the PowerRoller. On the other side of the PowerRoller a standard winding tube coupling can be applicated. The winding tube coupling is secured to the PowerRoller drive shaft with an adjustable screw. The winding tube coupling is supplied for various sizes of roll tubes. Other versions available on request.