The WIDOS 6100 can be used to process pipes and fittings out of PE, PP, PA and PVDF from OD 315 up to OD 630. The WIDOS 6100 features a double clamping device with quick clamping on the fixed and on the movable side. These are guided by 2 shafts. There are 2 flexible hoses with quick-action couplings for the connection to the hydraulic control unit. The double clamping devices are screwed to the steel pipe frame. The outer fixed clamping device can be easily dismounted by removing 3 screws in order to weld at difficult accessible places, e.g. in trenches or at branches of T-pieces. The remaining unit of three rings can be removed from the base frame and used for repair work. The WIDOS 6100 is thus a 4-ring and a 3-ring machine in one device.