Product Review

✔ Meets/exceeds: ISO7380
✔ Stainless steel 304, high strength and anti-corrosion in various environments
✔ Screw head style: button; screw drive style: hex socket , known as internal hex drives
✔ Easy to store : these screws come in an easy-use separated girds storage box

Item------------------Thread Length--------Total Length
M4 x 40mm-----------40mm/1.57"----------42mm/1.65"
M4 x 45mm-----------45mm/1.77"----------47mm/1.85"
M4 x 50mm-----------50mm/1.97"----------52mm/2.05"
M4 x 55mm-----------55mm/2.17"----------57mm/2.24"
M4 x 60mm-----------60mm/2.36"----------62mm/2.44"

Package Contains:
M4 x 40mm-----------10 Pcs
M4 x 45mm-----------10 Pcs
M4 x 50mm-----------10 Pcs
M4 x 55mm-----------10 Pcs
M4 x 60mm-----------10 Pcs
Total: 50 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 Button Head
Button head screws are similar to standard pan head screws, but have a curved top