400Pcs Threaded Inserts, M2 M2.5 M3 M4 M5 M6 Female Thread Metric Knurled Nuts Assortment Kit, Brass Heat Set Insert for Plastic and 3D Printing Components

The box they came in is superb for holding small parts, and the lid has ridges along all sides to prevent the “cross contamination” that these hardware assortments suffer from all too often. Each set of inserts were individually bagged, and I love it. I’m excited to use these little guys for my 3D printed projects!

Great first heat insert kit for 3D printing. They insert well and hold tight in multiple pla designs I've used, and they've held up well to repeated screwing and unscrewing. The variety and quantities are exactly what you want starting out.

Haven't really had to use these like I thought I was going to, but it has every little piece you'll ever need and lots of them. Nice little set and each size is in their own tray. Very handy.

Nice heat inserts, very consistent

Great kit

Needed these for my 3d printingThey work as intended

Nice Assortment. The worked great.

I used 4 of these threaded inserts on a recent 3D printed filament spool hanger project. Originally, I had used 4 screws into holes on the plastic printed part to hold the two parts of the assembly together. The parts I printed were for a weight bearing assembly and I really didn't feel good about using just screws into PLA as a long term solution. So, I purchased the Ktehloy 400 Pcs threaded inserts through Amazon. Using a hot soldering iron I inserted 4 of the M3 threaded inserts into one half of the assembly and I secured both halves of the printed assembly together using 4, M3 screws. The assembly is now very solid and has no problem supporting a full 2 lb spool of filament. The 400 piece box of threaded inserts should last me for quite a while but once these inserts are used up, I will buy another box.