Massive Heatsink For the Raspberry Pi 4 Single Board Computer. This thing is a beast! Check it out.
How to install, how it looks, how it sounds, and thermal numbers compared! GeeekPi ICE Tower CPU Cooling Fan ICE Tower Fan for Raspberry Pi 4 Model B & Raspberry Pi 3B+ & Raspberry Pi 3 Model B
Should be in stock soon: https://amzn.to/2lpnW49
Works for the raspberry pi 3b, raspberry pi 3b plus, and raspberry pi 4