- Type: Double bass strings - Quantity: Multiple - Material: Steel - Color: Silver, colorful thread - Features: Includes strings of different thicknesses Thank you for viewing! I am selling these strings because they didn't fit my instrument after I received them from a friend. According to my friend, they were used for about a year and a half. They are Helicore strings, but I don't know the specific type, so I hope someone who wants inexpensive used strings or can identify them by the tailpiece end will purchase them. There is no bag, so I will put them in a Ziploc bag and ship them in a brown envelope. Thank you.