Longer lasting high performance Olympia Pro CTB Bass Strings, are manufactured from the finest nickel-plated steel wire, wrapped around American hexagonal steel core wire, producing a higher magnetic response and provide brilliance, volume, sustain and strength. Olympia CTS strings are coated for improved corrosion resistance. This helps to slow oxidization and keep them sounding fresh. 1G - 045 2D - 065 3A - 080 4E - 100