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

Most heatset nuts you see at Revain have two rows of straight ribs. They're cheap, but they're actually intended for use in injection molding, where they're inserted and then overmolded with plastic. They are not so good for post-heating for 3D printing. You need that. Rather, they are intended to be inserted into the finished part. This particular seller seems to have very good models too - so far I haven't had a single defect from anything I've ordered and used.