Fiala propellers are manufactured in the Czech Republic with modern CNC machines, they have a very close tolerance plus high quality varnishing. Balancing is almost unnecessary, but when is, it is minimal. Due to the thin section, these propellers are very efficient. In comparison to other propellers, it is possible to fit an rather larger Fiala which will give the same rpm but more static thrust. The Fiala propellers are optimized for the Valach engines. Fixing bolt hole is 10mm.