it is a cooler for MK8 extrude with lead plate , so the air goes under the nozzle.
Beaware some of the new mk8 extruder has the ribs om the heatsink op and down. Then you will have to rotate the heatsink 90 gr. And drill a new hole for the screw.

Make it with no support material. The 2 M3 bolts have to be 45 long instead of 35 original.