Rutgerson violin pulley with jammer Smooth pulleys for high loads. The sides and discs of the Rutgerson blocks are made of high - strength composite material. Rutgerson Violinblock mit Unterbügel & Klemme Bezeichnung Ø mm Axe - Ø mm Cordage - Ø mm Loadkg Breakkg Weightg 300 Series 35 4 3 - 8 450 850 121 500 Series 50 5 4 - 12 700 1.250 270 600 60 6 6 - 14 1.150 2.100 375