330Pcs Threaded Inserts M2 M2.5 M3 M4 M5 Thread Knurled Nuts Assortment Kit Brass Heat Set Insert for Plastic and 3D Printing Components ,Widely Application: Nuts assortment kit can be embedded in a wide range of plastics, whether you're reinforcing 3D printed parts or assembling plastic components, this assortment gives you a wide variety of threaded inserts to choose from.