Contra Bass - H-31 (B-31) Single String / Harp Zither "Bergfee Steel" (red) Munich Tuning Scale length: 43,5 cm HARP ZITHER Bergfee Steel Red is our strongest zither string. It is made of finest steel with very little silk (on the steel core), wound with a fine silver plated wire. Powerful in tone (stronger and more aggressive sound than Nylon Blue). This string is also great for acoustic playing and electromagnetic sound transmission (sound pickup).