The stihl ms261 c m is a lightweight, convenient and durable professional chain saw. The ms261c m has up to five times longer filter life compared with the ms260. Fitted with m tronic electronic engine management system.the stihl ms261 c m has an easy clean hd2 filter, controlled delivery oil pump and practical features such as a stainless steel muffler, captive nuts on the sprocket cover and monocoque top cover with 3 quick release fasteners.up to 20% lower fuel consumption and up to 50% reduction in exhaust emissions compared to previous stihl models with stihl's 2 mix technology.the stihl ms 261 has a 50.2 cc 2 stroke engine and is available with a 13, 15, 16 or 18 inch bar.