Product Review

✔  Meets/exceeds: DIN 912
✔  Screw head style: socket cap; screw drive style: hex socket, known as internal hex drives
✔  12.9 grade alloy steel, minimum tensile strength : 176,900 psi
✔  Rust proof : black oxide finish covered with anti-rust oil
✔  Easy to store: these screws come in an easy-use separated girds storage case

Item--------Head Diameter-------Head Height------Thread Length------Total Length
M3 x 6-------5.5mm/0.22"--------3mm/0.12"---------6mm/0.24"---------9mm/0.35"
M3 x 8-------5.5mm/0.22"--------3mm/0.12"---------8mm/0.31"--------11mm/0.43"
M3 x 10----- 5.5mm/0.22"--------3mm/0.12"--------10mm/0.39"--------13mm/0.51"
M3 x 12------5.5mm/0.22"--------3mm/0.12"--------12mm/0.47"--------15mm/0.59"
M3 x 16------5.5mm/0.22"--------3mm/0.12"--------16mm/0.47"--------19mm/0.75"

Package Contains:
 M3 x 6-------50 Pcs
 M3 x 8-------50 Pcs
 M3 x 10------50 Pcs
 M3 x 12------50 Pcs
 M3 x 16------50 Pcs
Total: 250 Pcs

About Hex Socket Drives:
 Hex Socket drives, also known as Internal Hex drives, have a hexagonal hole in the center that requires an Allen key, also known as a hex key or Allen wrench
About Socket Cap Head:
 Socket Cap Head , also known as Allen head , have a recessed drive, and are commonly used when there is not enough clearance for a conventional wrench or socket. They are fastened with an Allen wrench, which is also called a hex wrench or hex key