Had a blade snap on my Ender 3 Pro's hotend fan and these were a perfect fit for replacement. I bought the 'High Speed' version and they run great. Definitely moves more air than the stock fan did and it seems a little quieter as well (hard to tell because the power supply fan is so loud). They fit perfectly in the stock casing without having to grind/drill/modify in any way.

Fans come with decent cable length and a nice JST-XH connector that I ended up cutting off. Spliced on some 2-pin DuPont connectors to wire it up. I've read some reviews that said these were wired backwards, but this was not a problem with the ones I received.
One thing worth noting is that you can buy these direct from WINSINN's website for about a dollar less (for the 5-pack) and with 1-meter length cables. The only reason I didn't buy that instead (could have ran the wiring all the way to the mainboard without having a splice in the middle) is that WINSINN's site said that because of Chinese Lunar New Year I'd have to wait at least 3 weeks or more to get them shipped. It wasn't clear if this affected parts stocked at the US warehouse, but I didn't want to chance having my printer down for that long.

Pretty good fans for my Ender 3 V2 3D Printer.

these fans really quieted my printers down barely notice them running now and they have been running almost 2 years now no issues and my printers run at least 130 hours a week

I wish I'd have found these sooner. I've purchased other fans to upgrade my 3D printers before. The fans I got were fine but they are nothing compared to these. To begin with, these fans came with pin connectors attached. This made installation very quick. No solder required. Second, these fans have a significantly higher CFM rating than the stock fans or the upgraded ones I got for my other printer. I can feel air coming from the vents on the bottom of my printer. I couldn't feel air movement before and there's no air moving out of my other printer with the "upgraded" fans made by another company. Third, I can't believe how quiet these fans are. I'm limited on space and so I have all of my printers set up in my bedroom. I can easily run a print at night on the printer with these fans and sleep right through it. Fourth (but probably most important), I'm planning to purchase two more printers so I'm very likely going to buy more of these fans. I would count these fans as a "no-brainer" upgrade, right along with an enclosure and a Micro Swiss All Metal hot end. Buy with confidence!!!

Easy no buck converter required.