The invention relates to a rectangular frame system with one to two discoid radiation filters, as well as a tanning module with such a frame system. The rectangular frame system has an upper plate, a lower plate and two to three margin members, two margin members being opposite one another and joining the upper plate to the lower plate, the upper plate having a first opening whose perimeter describes a circle, an ellipse, a rectangle or a polygon, and the lower plate has a rectangular second opening, the second opening having a greater area than the first opening, and at least two double spring clips are arranged at the two opposite margin members, which border on side of the frame system at which no margin member is provided, such that between the lower plate and the double spring clips a first radiation filter is clamped.