The EKLIND 19610 Metric Plain Double-Ball-Hex Key is the ideal tool for tightening and loosening fasteners. It has a 5 mm tip size, making it perfect for use with metric bolts. This hex key has an alloy steel blade that measures 6 3/16 in. long. The double ball end provides increased torque when using this hex key on nuts and bolts. The black oxide finish helps to protect against corrosion while also providing a firm grip on the handle. The EKLIND Hex Key is a durable tool you will want to have in your arsenal of tools.