1. Made of good hardness metal material with black zinc plated, it is rust and corrosion resistant, can be used in humid environment and has a long service life.2. HDD hard drive/disk shockproof mounting screws with shoulder for PC computer. Keep handy threaded screws commonly used to fasten hard drives, power supplies and expansion cards to the computer chassis.3. Please confirm the thread size and length before buying.Specification: Thread Size: M3 x 4.8mm(D*L)Thread Pitch: 0.5mmFit for: 2.5" HDDThread Size: 6#(3.5mm)Total Length: 6mm/0.24"Fit for: 3.5" HDDThread Count: 32Package Content: 200pcs x 6# Screw400pcs x M3x4.8mm Screw