A fluid chamber device for a reaction unit of a redox device, includes at least one first wall element and at least one second wall element which at least partially delimit a fluid chamber, and a sealing region which closes off the fluid chamber against a fluid exchange, in particular a gas exchange, in relation to a surrounding space. At least one of the wall elements, in an installed state, has at least one sealing contour in the sealing region, which is intended for providing a sealing effect and by means of which a spacing of the at least two wall elements in the sealing region is reduced in relation to a surrounding area of the sealing region.