High-quality material: all set screws are made of high-quality alloy steel, smooth edges, corrosion and rust resistance, not easy to break, but also can be used in harsh environments, sturdy and durable. Hexagon socket flat head screws set: for bathroom fixtures fixed screws, force uniformity, no offset, not easy to slip. Uniform thread pitch, obvious threads, no residual burrs, the threads of the set screws can be well grasped. EASY STORAGE: All flat head screws are stored in a clear sturdy storage box with compartments. Door handle screws are stored separately, well organized, easy to carry and find. No clutter during transportation, easy to use. MULTIPLE SCENARIO APPLICATIONS:Suitable for doorknob installation, faucet repair, light fixtures, knobs, pipe fixing, plumbing, and other small repairs in the store, garage, or around the home. Perfect for professional electricians, plumbers, construction workers, DIY enthusiasts and more. Packing list: you will receive a total of 400 pieces, 40 pieces of each size, sizes include: m3*3mm, m3*4mm, m3*6mm, m4*4mm, m4*6mm, m5*5mm, m5*8mm, m6*6mm, m6*10mm, m8*8mm, 5 hexagonal keys, the number of sufficient size to do both to suit daily use.