PRO-TECH 8 Pcs Hex Key Set MM are made of Premium chrome vanadium steel with a greater density at the points of the highest pressure, and such dimensioning and manufacture only increase their extreme power and durability. Holds screw tight, FIRST TIME – EVERY TIME. Does not weaken tool or encourage stripping. Allows for maximum torque without distortion. Rust proof and non-magnetic.
- Standard : DIN911
- Hardness : HRC 48-53
- Material : Chrome Vanadium Steel
- Surface finish: blacken to standard DIN 50938.
- Entirely hardened and tempered.