This professional-grade set of 22 SAE and metric long-arm hex keys is the perfect way to have all the hex keys you may ever need in one convenient case. Precision machined for a snug fit and made from chrome-vanadium steel for long life, hex keys are used for tightening and loosening machine screws with hexagonal heads. Long hex keys are especially popular with professionals working in tight spaces because they allow for extra torque. This 22-piece set includes a general selection of the most commonly used SAE and metric long-arm hex keys.