Genuine NGK BPMR6A Spark Plug 

NGK spark plugs come stock on many chainsaw brands, including Husqvarna, Jonsered and Stihl chainsaws, and are considered a high quality replacement spark plug. All spark plugs lose their effectiveness over time, and as the electrodes slowly becomes eroded from heat and oxidation, your chainsaw becomes harder to start. You can spend time cleaning the electrode and adjusting the gap, but the cheapest (time wise) and simplest thing to do is put a new plug in and go. This is a resistor type spark plug with a standard nickel center electrode.