M8 Size - 8mm Wrench Size. For Hexagon Nuts and Bolt Heads. M8 - 13mm Wrench Size. M4 - 7mm Wrench Size. M5 - 8mm Wrench Size. M6 - 10mm Wrench Size. M10 - 17mm Wrench Size. M12 - 19mm Wrench Size.
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