Usage Tips:the set contains 520 knurled threaded nuts, packed in a durable parent box. different sizes meet different requirements. Wide application: thread inserts for plastic suits for mobile phone housings, PC housings, plastic parts for motor vehicles, moulded parts, etc. It can also be used in 3D printing. Easy to use: insert into the hole of the component, heat the thread insert by soldering iron. After heating, press the thread insert into the component. Then cool down and tighten screws. Thanks to ultrasound or heat (soldering iron), the insert nuts can be easily embedded in a bag or through hole. Thanks to the straight knurled surface of the embedding nut, the nut fits firmly into the mounting object. Sizes And Quantity: M2x3:60pcs M2.5x3:50pcs M2x4:60pcs M2.5x4:50pcs M2x5:50pcs M2.5x5:50pcs M2x6:50pcs M2.5x6: 50pcs M3x4:50pcs M3x5:50pcs Different batches, different shooting angles and lighting, there are slight differences between the actual product and the picture, which will not affect normal use, and the plastic box style is random,can not be chosen the specific ones Colour:Photo Color Material:Brass Package Contents: 520x hot melt nuts Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.