Highest quality bits Prestacycle offers the highest possible quality 1/4″ hex tool bits for use on Bicycles and much more. Our bits are compatible with all Prestacycle hex-based hand tools, and are industry-standard to fit all other tools that use 1/4″ hex bits. Engineered for long life All Prestacycle Professional bits are made with hardened S2 steel, which is much stronger than most hand tools which are made of CRV Steel. S2 steel also resists stretching, preventing rounded edges on the bits that could damage bolts. We apply nickel-plating to all Professional bits to prevent marring to Stainless Steel, Aluminum and Titanium screws and to provide a long-lasting finish. Specific hex bits have micro surfacing to reduce slippage when in use. HEX: 3mm, 4mm, 5mm (3) Precision hardened S2 steel Nickel-plated Professional bits in a Patented Bits Carrier. Stronger and longer lasting than any other tools made for bicycles. Since worn heads can damage bolts, these bits protect your components. Covers the most common HEX sizes.