Package content:
100pcs M3 Screws,
60pcs M3 Lock Nuts,
60pcs M3 Hex Nuts.
M3 x 10mm 20pcs ,
M3 x 12mm 20pcs,
M3 x 16mm 20pcs,
M3 x 18mm 20pcs,
M3 x 20mm 20pcs

[About Socket Cap Screws]
Socket cap screws are often used due to quality issues, or stripping problems associated with hex head screws. Cap screws also often round out better than hex head screws, since hex heads require extreme pressure with repeated rounding. Hex Wrenches Hex wrenches (allen wrenches) are used to fasten bolts and screws with a hexagonal socket.