Info from Manufacturer: The GHS Bass Boomers® are the classic Power String and they have been for years. Today they are one of the most popular bass strings in the world and are used by bass greats including the legendary Flea. Like the guitar version, Bass Boomers® feature a nickel plated steel wrap that provides brilliance, volume, sustain and strength, unlike any other bass string. 3036 (.050) 3037 (.070) 3038 (.090) 3039 (.107)