Inner vessel of a simulation chamber, wherein at least two hook-shaped attachment elements are provided for attachment to a housing of the simulation chamber, wherein the inner vessel, in the shape of a cube, comprises an inner space, five side walls and a door side, wherein at least one sheet metal strip is arranged on the inner vessel which has a first longitudinal edge and a second longitudinal edge, each essentially parallel to a longitudinal axis of the sheet metal strip, wherein the sheet metal strip comprises at least one, preferably numerous, recesses, each of which forms one of the hook-shaped attachment elements, wherein the recess comprises an edging with at least: - a first edging side having a first end and a second end, - a second edging side having a first end and a second end, - a third edging side having a first end and a second end, wherein - the first end of the first edging side is arranged on the first longitudinal edge of the sheet metal strip and the first edging side is arranged at a first angle (β1) to the first longitudinal edge which is smaller or equal to 90°, - the first end of the second edging side is arranged on the second end of the first edging side and the second edging side is arranged at a second angle (γ1), which is smaller than 180°, to the first edging side and preferably essentially vertical relative to the longitudinal axis of the sheet metal strip, and the first end of the third edging side is arranged on the second end of the second edging side and the second end of the third edging side is arranged on the first longitudinal edge, wherein the third edging side comprises at least - a first segment with a first end and a second end and - a second segment with a first end and a second end, wherein - the first end of the first segment is arranged on the second end of the second edging side, - the second end of the second segment is arranged on the first longitudinal edge, and - the first segment is arranged at an angle (ε1) relative to the second segment which is smaller than 180°. - a first edging side having a first end and a second end, - a second edging side having a first end and a second end, - a third edging side having a first end and a second end, wherein - the first end of the first edging side is arranged on the first longitudinal edge of the sheet metal strip and the first edging side is arranged at a first angle (β1) to the first longitudinal edge which is smaller or equal to 90°, - the first end of the second edging side is arranged on the second end of the first edging side and the second edging side is arranged at a second angle (γ1), which is smaller than 180°, to the first edging side and preferably essentially vertical relative to the longitudinal axis of the sheet metal strip, and the first end of the third edging side is arranged on the second end of the second edging side and the second end of the third edging side is arranged on the first longitudinal edge, wherein the third edging side comprises at least - a first segment with a first end and a second end and - a second segment with a first end and a second end, wherein - the first end of the first segment is arranged on the second end of the second edging side, - the second end of the second segment is arranged on the first longitudinal edge, and - the first segment is arranged at an angle (ε1) relative to the second segment which is smaller than 180°.