KeeYees 3D Printer Cooling Fan DC 24V 50mm x 50mm x 15mm 5015 and 40 x 40 x 10mm 4010 with Fan Protection Cover for Hotend Extruder Heatsinks for Arduino

Was just looking to replace one of my 40x40 fans but the 4 fans in a box was a deal I couldn't pass on. Fan replaced on my 3D printer works great.

Update:Contacted seller about the defective fans and they offered to replace them free of charge. The new ones took a while to arrive but they work as expected. I cannot change to five stars, but for the price I am satisfied with my purchase even with the wait time.Original review:The set includes 4 total fans, 2 blowers and two 40x40mm fans.The two blower type fans did not work at all. Already spliced in several extra feet of wire on one of the blower fans, so cannot return to Amazon. When first fan didn't work, I assumed I may have goofed with the wiring, and tried the other fan with stock wiring. Still not working. Plugged in 40x40mm fans one at a time into the same plug on my printer, and both of them are working without issue.I purchased this set especially for the two blower fans, and not the 40x40mm ones, but I suppose I have a couple of expensive spares for my printer's hot end.

The 2 square 40×40 fans wiring hot + and ground - are wired to the connector Opposite wireing of the shell 50x50 fans. The "shell" fans both worked and after I reversed the wiring polarity the 2 square fans actually worked.

None of these fans where worth a damn! I ended up putting the old fan back in my humidifier. The old fan works better and is quieter than any of these fans were.

They are quiet, very quiet. So quiet that I had to visually check that the fan was running, because putting my hand near the extruder fan left me wondering if there was any air flow. There is, it's just a very, very small amount of air flow. Just for kicks I wired one directly to the 12v output from the power supply. Exactly the same result. I ended up having to replace the throat on my V6 clone because filament had melted up into it and caused a clog. Don't use these for a hot end unless you have very little need for air flow.

They were perfect and quite for about the first 5 printsm now they vibrate and are extreamly loud. All 4 fans BTW. Disappointed.

Decent little fan, except the cable is WAY too short.I had to extend it myself. The plugs on the jst connector are backwards for my printer's motherboard, too. I had to manually reverse them, which was very tedious.

The fans are at best a bad joke. No air flow! The labels fell off before removing from box. Labels falling off was probably the smartest thing they did. I too wouldn't want my name on them. Bought them for a 3d printer I was converting from 12v to 24v. I ended up having to use my old 12v fans at 50%.The airflow is so slow, none of them could move a feather. You can't feel any airflow. Pointless. How could anyone sell these with a straight face.ProsQuiet, but so is no fans.I guess we should be impressed that they can ship something while rolling over laughing.ConsSeller