This is a simple but very effective fan optimizer for the ender 3 printers.
It uses the original block to convey the flows of the two fans in the right directions with minimal interference: the flow of the heating body cooler travels horizontally out of the bottom and from the slots on the left side while the flow of the nozzle cooler flows from the four sides around the nozzle thus increasing its effectiveness.
This model is also very easy to print as it does not require any support.
According to the configuration of your printer and your slicer, the printing process can vary between 70 and 90 minutes.
Since I printed and assembled this accessory I have found benefit in the use of ABS filaments (although it is not the miraculous remedy ... laugh)