string length 104cm, dark and warm sound, easy to play.

Bruxelles c`1870, 4 string bass, carved maple back, string length 104cm,

Augsburg 1771, 5 string double bass, string length 110cm.

a 4 string double bass, Martin Diehl, Mainz, c´1790, flat back, string length 104cm, M. Diehl worked with Helmer in Prague before 1770.

a 5 sting double bass, Markneuenkirchen school, c´1850, sting length 108cm