iExcell 50 Pcs 12.9 Grade M4 x 20mm/25mm/30mm/35mm/40mm Alloy Steel Hex Socket Head Cap Screws Bolts Assortment Kit

✔/u2003 Meets/exceeds: DIN 912, ISO 4762 ✔/u2003 Material of Screws: 12.9 grade alloy steel, hardness: HRC 39-44, tensile strength: 1220N/mm² ✔/u2003 Screws Rust proof: black oxide finish, covered with anti-rust oil ✔/u2003 These screws and Hex Key come in a separated girds storage case Sizes ------------ Thread Length ----- Total Length M4 x 20mm-----------20mm--------------24mm M4 x 25mm-----------25mm--------------29mm M4 x 30mm-----------30mm--------------34mm M4 x 35mm-----------35mm--------------39mm M4 x 40mm-----------40mm--------------44mm Package Contains: M4 x 20mm---------10 Pcs M4 x 25mm---------10 Pcs M4 x 30mm---------10 Pcs M4 x 35mm---------10 Pcs M4 x 40mm---------10 Pcs Hex Key ---------1 Pcs Total: 51 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 screws, also known as Allen head screws, 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'