The STIHL MS 171 is part of the lightweight generation of STIHL chainsaws with reduced – emission technology—a significant benefit for users because it saves fuel even as it cuts exhaust emissions. The MS 171 also has the STIHL pre-separation air filter, which can extend filter life up to five times over previous models. Note: Not available for purchase or delivery in California., Available at your Dealer , Unavailable at your Dealer