The NGK BPMR4A spark plug is used to create a spark, which will then cause the fuel to ignite in the engine in compatible models so the machine can start. Spark plugs will eventually need to be replaced. They will go bad or become worn out with regular use and will no longer provide a proper, reliable spark. When they do not operate properly, it will make the engine more difficult to start. In some cases, the engine will not start at all. The spark plugs will need to be replaced. To test the quality of the spark plug, owners can use a multimeter. Additionally, they can check to look for signs of corrosion with the spark plugs to see if they might be going bad. This is an authentic OEM NGK BPMR4A spark plug replacement that can be used with lawn mowers, snowblowers, generators, and other small engines. Compatible brands include Toro and Lawn-Boy.