Nobody knows flatwound bass strings better than thomastik-infeld. Spirocore strings by thomastik-infeld have been legendary among upright bassists for decades. Now the electric bassist can also experience the thomastik-infeld sound. Thomastik-Infeld utilizes a highly pliable steel core which is wrapped with a silk inlay. The outer winding is a true ribbon flatwound constructed of a special nickel alloy. The result is an incredible depth of tone and an enhanced fundamental which is unavailable from any other flatwound.