With this fan duct you can improve the hot end cooling of a Zonestar P802Q. The fan duct was designed for a hot end heat sink with a diameter of 22.2 mm and a 40 mm fan (= original parts of P802Q). As you see on the pictures the fan duct will be installed inside of the metal box of the extruder. The installation is a bit tricky because there is not much space. I considered the screw head of the X-bearing (SCS8UU) and the rectangle nozzle heater. That's the reason for the dimples and asymmetric design.
Pay attention that the screw of the Teflon tube can be screwed in easily (let the fan screws loosely at first). The thread of the heat sink and the bore of the extruder housing have to be concentric. If not, you have to move the fan duct a bit up or down to bring the dimples of the fan duct at the position of screw heads of the X-bearing . After the Teflon tube is installed tighten the fan screws.
Optional: You can use some super glue to fix the M3 nut on the fan duct (might facilitate the installation).