A hydraulic cylinder unit for connection to a wire line riser tensioner system includes a hydraulic cylinder comprising a cylinder piston separating a first cylinder chamber from a second cylinder chamber. A low pressure tank is arranged as a closed cylinder. A first conduit is inserted into the closed cylinder and provides a fluid communication between the low pressure tank and the first cylinder chamber. A second conduit provides a fluid communication between a high pressure fluid reservoir and the second cylinder chamber. A feedback conduit provides a fluid communication between the first cylinder chamber and the second cylinder chamber. A valve element comprising at least one valve is configured to be in a fluid communication with the at least one first conduit and the at least one feedback conduit. The valve element is configured to provide a reversible switching between a first alternative configuration and a second alternative configuration.