Simply the most popular commercial chain saw in the world for felling, trimming and all commercial and forestry applications. The MS 661 C-M is a rugged all-rounder equipped with STIHL's environmentally friendly 2-MIX engine technology for less fuel consumption, less emissions and outstanding cutting performance. In addition the MS 661 C-M features a heavy duty (HD2) air filter system with a radial seal which keeps out fine dust particles combined with the compensator the MS 661 C-M can now be used for 20% longer than the MS 660 before a filter clean is required. The MS 661 C-M is fitted with STIHL's M-TRONIC electronic engine management system which enables the saw to automatically adjust to varying fuel grades, changes in altitude and temperature and as there are no manual carburettor adjustments starting this saw is easier than ever before, simply push the start level to the on position and pull. The MS 661 C-M is now the only choice for professionals.