Have the same one as @ntblowz, with the suction cup. The newer model, with springs, looks much better.
And it really works. In the end I only used to do a torture test with my X-S20, under 12 o'clock sun and around 35 celsius, and put the camera to record 6.2k 10-bit 4:2:2. Without the fan, the camera over heated around 25 minutes; with it, went over an hour (the SD card was filled before a temperature shutdown).