A device for controlling temperature in a reaction chamber is disclosed. The device comprises: a bladder assembly comprising a housing dimensioned to hold a reaction chamber disposed within an interior volume of the housing; and a first temperature-control bladder disposed within the housing, the first temperature-control bladder is configured to receive a temperature-control fluid and comprises a flexible, heat conductive surface that comes in contact with at least a portion of an exterior surface of the reaction chamber after receiving the temperature-control fluid. Also disclosed are a bladder thermal cycler, a temperature-control bladder assembly and methods for producing a thermal cycle in a reaction chamber.