Description: A set screw is a type of screw generally used to secure an object within or against another object without using a nut. The most common examples are securing a pulley or gear to a shaft. Set screws are fully threaded and has no head projecting past the major diameter of the screw thread. These set screws are driven with an internal-wrenching hex socket drive. Features: These set screws are made from 12.9 grade alloy steel for high hardness, durability and long service life. They are multipurpose hex socket head set screws that you can simple drive with a hex key. There are 10 common sizes and you can concentrate on your project without worrying about not having the correct screws. Get these total 200 pieces screws so you won't be running off to the hardware store for a set screw for quite a while. Well packed and assorted in a transparent resealable box for convenient carry and storage. Specifications: Material: 12.9 grade alloy steel Color: Black Type: Hex Socket cup point Size and Quantity: 20pcs M3x3mm 20pcs M3x4mm 20pcs M3x6mm 20pcs M4x4mm 20pcs M4x6mm 20pcs M5x5mm 20pcs M5x8mm 20pcs M6x6mm 20pcs M6x10mm 20pcs M8x8mm Box Size: 13 x 6.5 x 2.3cm / 5.11 x 2.56 x 0.9" Package Includes: 200pcs x Screws