SET OF DOUBLE BASS STRINGS Helicore '' Solo '' nickel wound 3/4 medium tension. The Helicore para strings have been specifically tailored and tuned for the notes: AEBF #, a pitch higher than standard tuning. They are made with a core composed of various braided steel strands, which produce a warm tonal quality with an excellent response when playing with the bow. The core design makes the strings very easy to play under the left hand. The cushioning has been conceived for the use of the arch, making them ideal for solos.