For the people who are not familiar with the car washing tools, mostly, foam gun and foam cannon will be categorized the same product with two different names. However, when we are washing our cars , those two are different tools work for similar function. The main differences between them is that foam cannon is used with pressure washer, while gun attaches to a standard hose. People prefer convenience likely to use foam gun;others favor stronger cleaning power will choose foam cannon. Both foam cannon and foam gun can make washing your car more effective.