The first commercial rilling tool on the market and still popular! The Super Riller comes as standard with the Medium (0.75 mm) structure steel. The range of optional structure steels for the Super Riller includes: Extra fine 0.33 mm. Fine 0.5 mm. Medium 0.75 mm. Coarse 1.0 mm. Coarse 2.0 mm. When warmer than -2°C, the 0.75 mm or 1 mm structure steel is used. Gives a major improvement when very wet snow.