D'Addario Double Bass Helicore Pizzicato Nickel Wound Extended E Heavy 3/4, HP615-H

"The standard Helicore bass strings, introduced in 1994, have met with worldwide acclaim. These stranded steel core strings (standard H610 models) provide unprecedented ease of bowing and the warm, natural tone one would expect from a fine gut core string.

In 1996, with the help of D'Addario Musician's Advisory Board members, D'Addario completed development of additional Helicore double bass string varieties. The new strings include the HP series, designed specifically for the bassist who plays pizzicato, HH series, for those who play a broad range of musical styles, and HS series, for solo orchestral work.

The HH series has improved pizzicato sustain over the standard orchestral models, yet still provides excellent bow response for arco passages. The HP series provides even more sustain and "growl" when played pizzicato. The HS series is a solo tuning version (one full step above normal pitch) of the standard orchestral Helicore strings."