200Pcs/Box M3 Countersunk Flat Head Hex Socket Screw Bolt Machine Fastener Assortment Set Description: These flat head hex socket screws are made of 10.9 grade alloy steel, which are resistant to rust and corrosion. There are 8 thread lengths for you to choose from, which can be generally used in home and office appliance, machinery, furniture, etc. Features: 1. 10.9 grade alloy steel material has good strength of extension and corrosion resistance in many environments. 2. Countersunk head enables driving where it doesn't have sufficient space for wrenches.  3. Ideal for use in confined areas where the head needs to be flush or below the surface. 4. Used for fasteners in home and office appliance, communication equipment, ship assembly or other machinery industry. 5. Screws with 8 common thread lengths are well packed in 8 compartments and assorted in a transparent plastic box for convenient use and storage. Specifications: Material: 10.9 Grade Alloy Steel Color: Black Thread Lengths: 4mm(30Pcs), 6mm(30Pcs), 8mm(30Pcs), 10mm(30Pcs), 12mm(20Pcs), 16mm(20Pcs), 20mm(20Pcs), 25mm(20Pcs) Thread Diameter: 3mm (M3) Box Size: 13 * 6.5 * 2.3cm / 5 * 2.6 * 0.9inch Quantity: 1 x Box of 200Pcs Screws Package Weight: 138g Type: Flat Head Hex Socket Screw Function: Fastener  Package Includes: 1 x Box of 200Pcs Screws