In difficult situations, the fan specialist ebm-papst therefore relies on a “twin tandem”. Two serially connected S-Force fans give rise to the CR 8200 J (co-rotating) fan (Figure 1). With up to 232.5 m³/h and 1268 Pa, it provides more air flow volume and pressure than special solutions. Unlike parallel operation for which an intermediate distance between the fans is required, the cubic fan saves valuable space and measures only 80 × 80 × 80 mm. The “tandem” is based on two J 8200 S-Force fans connected via a 4-mm-wide honeycomb composite structure. The fan, which weighs only 370 grams, moves air very efficiently. The two fans are completely identical – the motors run in the same direction, and the fan blades of the rotors are curved in the same direction. Because of the swirl reducing effect of the honeycomb structure, the second fan can again contribute efficiently to the increase in air pressure. Both engines are individually adjustable and thus allow for the optimal adjustment of air quantity or pressure increase for each cooling requirement (Figure 2). The new fan is available in the 12, 24, or 48 VDC version.