280Pcs M3 Head Hexagon Socket Screw Nut Set, Black Socket Head Screw, Length 4/5/6/8/10/12/16/20/25mm

The case it comes in is very flimsy, and could cause mixup of the screws if stored in a bag or tool box.Worse: it could open and cause a very bad day of sorting the screws.Otherwise, for 3D printing, you will have all the dimensions of M3 that you may ever need.If this is your usecase, I also recommend buying heat inserts instead of the nuts.

I bought this to use in my various 3D printing tinkerings and they do come in handy quite a bit. I have little use for the two smallest sizes because the threads are too fine for them to have enough strength (I use better tapping screws for that), but the others are great.Personally I didn't find any issues with the box, nothing has gotten mixed besides a screw accidentally dropped in the wrong space, and I'm still using that same box nearly a year later.I would warn you that if you need a particular screw size far more often than others, you'll run out of it quick. This has 20x of each size.

I ordered these, because I wanted M3x12 black hex top, for replacing the chrome pole screws on my electric guitar pickups. When I ran out 12mm, I tried using the 10mm and 14mm, but their shade was different. While the 12mm is dark and glossy, the 10mm and 14mm are light and mate (like washed-out). I ordered a second box and hope it fixes the issue.

used for 3d printed projects

Good quality set that I bought for a 3D printer. I'm notorious for reefin' on things more than they need and I haven't stripped any of these yet. So that's a plus.