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