The Echo CS-3510AC is similar to the Echo CS-3510ES but with the addition of having a auto choke feature on the carburettor. The engine is a 34.4cc professional grade engine with the Echo ES-Start pull start system. The auto-choke system fitted to the carburettor helps with quicker starting procedures and a solenoid valve in the carburettor helps control the amount of fuel required depending on the engine temperature. The carburettor on this saw also has the anti-icing system to prevent the carburettor freezing in colder months. The same great features found on the regular CS-3510ES are also present on this saw including side adjustment, light weight build, and a excellent power to weight ratio. Ideal for domestic and semi professional users.