A fluid-operated power tool has an engaging part with a turnable engaging element for engaging and turning a threaded connector, and a power drive part with a power drive operative for turning the engaging part, wherein the power drive part includes a fluid-operated cylinder-piston unit, the power drive part having an end spaced from the engaging part and provided with an inner opening with a first connection, and a reaction member formed as a reaction arm which is turnable between a plurality of positions around an axis of the power drive part and fixable in each of the positions, the reaction arms having a projection which is insertable in the opening and being provided with second connection with the first connection so as to connect the reaction arm with the power drive part.