Size: 12 MMLong Arm Length Range: 119mm - 125mmShort Arm Length Range: 43mm - 45mmMaterial: Hardened Alloy SteelA Hex Key Is A Six-Sided Shaped Bar Bent At A 90 Degree Angle At One EndDesigned To Be Inserted Into A Like-Sized, Hollow Recess Of A Socket Screw To Manually Tighten Or Loosen The FastenerEither Side On The Key Can Be Used For Convenience