Stihl and Husky have two numeral codes like 13RM, 33sg etc. The second digit for Stihl and husky of Swedish manufacture 1=1.1mm=0.043 3=1.3=0.050" 5=1.5mm=0.058" 6=1.6mm=0.063" Stihl puts a sheet in their chain packages sort of explaining it.
