An apparatus for tightening or loosening fasteners (131, 731) including: a first and a second receiving member (111, 711), rotatably supported in the apparatus, for receiving a first and a second fasteners (131, 731); a first and a second device realized as a first and a second torque power tool (100, 700) for effecting rotation of the respective receiving members (111, 711) to tighten or loosen the respective fasteners (131, 731); wherein the devices for effecting rotation are either pneumatically or hydraulically driven, a device for controlling an operation parameter of each device for effecting rotation to maintain a difference between the operation parameters within a predetermined value, the operation parameters include either hydraulic or pneumatic fluid pressures or flow rates, electrical circuit parameters such as current, voltage or magnetic field, torque output values, rotation speeds, or a combination of such, wherein during operation if the difference in the operation parameters exceeds the predetermined value the device for controlling regulates the operation parameter of the respective devices for effecting rotation by either lowering the operation parameter of the device with the higher operation parameter, raising the operation parameter of the device with the lower operation parameter or both raising and lowering the operation parameter of the respective devices until the difference in the operation parameters returns to within the predetermined value, characterized in that the devices for effecting rotation (100, 700) are connected, the connector including: a first force-transmitting element rotatably attachable about a turning force axis of the first device for effecting rotation; a second force-transmitting element rotatably attachable about a turning force axis of the second device for effecting rotation; and wherein the second force-transmitting element is either rotatably attachable about, extensibly and retractably attachable along, or rotatably attachable about and extensibly and retractably attachable along at least a distal portion of the first force-transmitting element. a first and a second receiving member (111, 711), rotatably supported in the apparatus, for receiving a first and a second fasteners (131, 731); a first and a second device realized as a first and a second torque power tool (100, 700) for effecting rotation of the respective receiving members (111, 711) to tighten or loosen the respective fasteners (131, 731); wherein the devices for effecting rotation are either pneumatically or hydraulically driven, a device for controlling an operation parameter of each device for effecting rotation to maintain a difference between the operation parameters within a predetermined value, the operation parameters include either hydraulic or pneumatic fluid pressures or flow rates, electrical circuit parameters such as current, voltage or magnetic field, torque output values, rotation speeds, or a combination of such, wherein during operation if the difference in the operation parameters exceeds the predetermined value the device for controlling regulates the operation parameter of the respective devices for effecting rotation by either lowering the operation parameter of the device with the higher operation parameter, raising the operation parameter of the device with the lower operation parameter or both raising and lowering the operation parameter of the respective devices until the difference in the operation parameters returns to within the predetermined value, a first force-transmitting element rotatably attachable about a turning force axis of the first device for effecting rotation; a second force-transmitting element rotatably attachable about a turning force axis of the second device for effecting rotation; and wherein the second force-transmitting element is either rotatably attachable about, extensibly and retractably attachable along, or rotatably attachable about and extensibly and retractably attachable along at least a distal portion of the first force-transmitting element.