Last up to 3X longer – Amazing Tone – Effortless Feel – High Output – Great Sustain Cryogenically treated to enhance tone and feel while creating a longer lasting and more durable string. The cryogenic process removes transient material that produces harsh highs and muddy lows that kill the sound and life of your string. Made of 8% nickel-plated steel outer wrap on tinned Mandolin wire hex-core, Blue Steel strings have been best sellers worldwide for over 30 years and are used by the best musicians everywhere. Once you try Blue Steel strings you`ll be hooked. They feel great, ring true, are durable and long-lasting with harmonics you won`t find in any other string.