✔Meets/exceeds: DIN 7991
✔Screw head style: flat Head, known as countersunk head, countersunk angle: 90 degree
✔Screw drive style: Internal Hex drives, also known as Hex Socket Drives
✔Material of Screws: Stainless steel 304, high strength and anti-corrosion in various environments
✔Material of Hex Key: chrome-vanadium steel, nickel plated
✔Easy to store: these screws and hex key come in an easy-use separated girds storage case

[ Sizes ]------------[ Total Length ]
M4 x 20-------20mm/0.79"
M4 x 25-------25mm/0.98"
M4 x 30-------30mm/1.18"
M4 x 35-------35mm/1.38"
M4 x 40-------40mm/1.57"

[ Package Contains ]
M4 x 20-------10 Pcs
M4 x 25-------10 Pcs
M4 x 30-------10 Pcs
M4 x 35-------10 Pcs
M4 x 40-------10 Pcs
Hex Key -----1 Pcs

[ About Internal Hex drives ]
Internal Hex drives, also known as Hex Socket Drives, have a hexagonal hole in the center that requires an Allen key, also known as a hex key or Allen Wrench
[ About Flat Head ]
Flat head screws are designed to fit flush to the surface when used with countersunk holes.