My experience with these nozzles: At first, these nozzles seemed good but then I found that many of the nozzles have threading issues. I am not gonna ruin the internal thread of my hot end by forcing these nozzles in to work. Then, a few weeks later, I noticed on a nozzle that did thread okay, did not lay down a tried and true filament, even after a full hot-end purge and clean. At first, I blamed it on a new filament brand that I hadn't used before but after changing the nozzle, it worked just fine. After using these nozzles, I believe that about half of the .4mm are truly usable. Yes, they are cheap but people need to know this.