2 Packs Cooling Fan for 3D-Printer Ender 3 V3 SE/Ender 3 V3 KE/CR10 SE of 3D Printer Parts & Accessories, Included 24V 4010 Extruder Turbo Fan and 24V 2510 Fan with 2 Pin Terminal

both fans went, bought these, work well

Like the other Kobra S1 reviewers, I have reservations about this set. They seem well made and nearly identical to the OEM hotend. However, it does appear that the throat tube is PTFE and not ceramic as another reviewer mentioned. No matter, since they're brass nozzles, I planned on using them for "normal" filament anyway. I've been running ABS on my OEM nozzle, so I planned on using the new 0.4 nozzle for PLA since any remnant of ABS in the nozzle can mess up PLA, and vice versa - PLA remnants can burn up and clog the nozzle when using it for higher temperature materials.I installed the 0.4 hotend and started a bed levelling operation and got an "abnormal heating" error. Unplugged, replugged, and still the same error. I plugged the 0.6 hotend in and set the temp at 170c, it ramped up and cooled down fine. I plugged the 0.4 back in and tried the same, it ramped up slowly, but when I changed the temp to 140c, I got an NTC error. My only conclusion is that the heater, thermistor, or both are either mismatched for the machine or defective, so I'm returning for a replacement. I'll update this further if there are issues with the replacement hotends.(Note: You do not have to fully install the hotend to test it. Bring your printhead to the front center, remove the fan shroud and carefully unplug the fan, unplug your hotend and remove it to get it out of the way. The plug has a squeeze clip on the back, you can't just rock the connector out. Then plug in the new one and let it dangle, go to the prepare menu and set the temp to 140 or 170, watch the screen for how fast the temp rises, it should be pretty fast. Set it to some lower temp and wait patiently for it to go down and stabilize, set to zero and let it cool completely before fully installing it or removing it. Any errors mean it's defective. Also, use a flashlight, when the printer errors out the interior light goes off, and you need to turn it off to replace and test anyway.)

Avoid this hot end. Definitely not the correct the thermistor and the nozzle looks like a cheap nozzle. Ambient temperature of the room is around 21c and the hot end is reading 46c. I've been 3D printing for 6 years now and have built several custom printers so this is a review you can trust. I'm not bothering with a return since I have a hip injury and the only free return options are dropping off only at inconvenient locations. For now will transfer the heater and thermistor from an original anycubic hot end to get by for now so I can run a 0.6 nozzle.

Hot end fan is awesome. Quiet, effective, everything you could want. The parts fan is strong, borderline too strong. I had print detaching from the plate and I think it was due to the increased airflow cooling the plate

As expected

Edit: they offered me a refund which is honest. Changed from one star to 3 .Wires pulled out upon trying to install in my machine. Save your money and buy from a different supplier.

These work as intended so far. They claim to be ball bearing fans in the listing. If that is the case they should last a long time. If they are plain old sleeve bearing fans instead, then they won't last very long at all. So I hope these are truly ball bearing fans. I'd have to basically destroy them to verify it though. I'll just use these until the fail and then decide what to do. Finding real dual ball bearing fans of this size is challenging. I think I paid $10 for just one 4010 dual ball bearing fan the last time. The little 2510 fans are so cute, they are literally 1 inch by 1 inch. Finding high quality 2510 fans is really, really hard. So I hope these are ball bearing and they last.

So, this 2nd version of the K1 nozzle hotend setup is nice and a slight knock off of micro swiss setup. The issue with this new setup is, there is ZERO mention that you need thermal paste on your nozzle thread and hand tighten only. If you do those 2 things, these last. If you do not do those 2 things, it will seize after 2-3 uses. Even if you hand tighten, the thermal paste is mandatory for longevity or you will buy many hotends. I have learned that Creality makes a good product, but have poor directions. It is sad, because the product can be amazing for the most part. Again, hand tighten or 1/8 turn with wrench. And, add thermal paste to thread. Thermal paste is less than $10 and some suppliers provide a small pack of it (they also do not give direction....lol) my information came from a YouTube video.