Review on GeeekPi Raspberry Pi 4 Armor Case with Cooling Fan - Premium Aluminum Alloy Case for Ultimate Cooling Performance! by John Beltran

Quiet (the fan is not even audible and rotates rather slowly), but cools the Pi 4b without any problems. Much cooler than just chip heatsinks and a 40mm fan. The best case I've used so far. It simply goes with you and cools all warm parts. The only minor issue is that the acrylic window for the wifi reception and cable grommet sits loose in the slot, so I just cut out some very small strips of double sided tape and glued them to the top and bottom grooves holding the window. Amazing coverage! I just bought another one to replace a crappy plastic case, 40mm fan and chip heatsink which are horribly cold and noisy. This case isn't even audible, but cools surprisingly well since it's a heatsink.