The fan can physically fit on the be quiet! Pure Rock Slim 2 CPU cooler, but it is not the original or recommended fan for that cooler. The Pure Rock Slim 2 comes with a 92mm Pure Wings 2 PWM fan, while the NF-A15 PWM chromax.black.swap is a 140mm fan. The cooler is designed for a 92mm fan size, so using a 140mm fan may not be compatible with the mounting points or the cooler's size constraints. Therefore, this fan is not suitable for use on the Pure Rock Slim 2 CPU cooler.