Review on [initeq] M3-0.5 Threaded Heat Set Inserts for 3D 🔩 Printing (50, Short): Enhance Your 3D Printing Experience with Premium Inserts by Wayde Lash

Very easy to insert and stick! I received M3 .5 inserts (short) and preferred the 5.4mm diameter x 4mm deep cavity. I've used my cheapest pointy tip non-temp controlled soldering iron and haven't had any problems with it so far. They HAVE a top and bottom, see the second from the left on my test stick in the picture. I installed the insert and used a long screw there and pulled as hard as I could with pliers to lock the channel a couple of times. It's very well established. I like using them!