The Klein Tools Pro Folding Hex Key Set, No. 70550, equips professionals with 11 extended-reach blades in one convenient tool. Its industrial strength blades, including the high-leverage 1/2" key, are built to stand up to harsh jobsite conditions. The blades open independently up to 270 degrees and are made of tough, heat-treated alloy steel. The hex-key ends are square-cut for a secure, full-depth fit and have maximum contact with the socket to prevent slippage and stripping. The set includes the most frequently used hex key sizes: 1/2", 3/8", 5/16", 1/4", 7/32", 3/16", 5/32", 9/64", 1/8", 7/64", and 3/32".