A set of strings from PSD BASS 99 series, designed for 4-string bass. A specialist string design that utilises the contact core concept. That is the same as piano strings whereby only the core is exposed over the bridge of the instrument. The increased sustain and presence is unmatched by any other string, at the same time freeing up those upper harmonics that would otherwise be lost. The strings are made of stainless steel with roundwound winding.