Paintball is a sport similar to Airsoft in which participants eliminate opponents from play by hitting them with paint filled, breakable, gelatin paintballs shot from a carbon dioxide or compressed-gas-powered "paintball marker". Airsoft however, shoots 6mm plastic pellets powered by electric motors that compress a spring and release it. Airsoft guns are much more realistic due to the fact that there is no hopper or air tank. Speedball is virtually non-existent in Airsoft. Yet in paintball it is a very large part of the sport, along with woodsball and scenarioball.----------- Games can be played either indoors or outdoors and take various forms, of which some of the most popular are woodsball, scenario, X-Ball and speedball. Rules for playing paintball vary widely, with most designed to ensure that participants enjoy the sport in a safe environment. The sport requires a significant amount of equipment. A game of paintball usually involves two opposing teams seeking to eliminate all of the other team's players or to complete some other objective, such as retrieving a flag, eliminating a specific player, or other paintball variations. Depending on the style of paintball played, a paintball game can last from seconds to days, although typical woodsball games are five to thirty minutes long.