The 'guns' used in the game of paintball are referred to as markers. There are several different types of markers. Carbon dioxide markers are the most common, but other high-pressure air systems are available.

Markers are sometimes adjustable. Some can become automatic, and some can fire at variable velocities. These adjustable settings highly increase the effectiveness of the marker. With the automatic setting enabled, one depression of the trigger would fire multiple shots. This would generally be used in close combat situations so that the player would have a higher chance of hitting his or her target(s). The velocity your marker shoots at should be changed depending on the range of the target. A faster velocity results in increased accuracy - so when the range to target is high, you would want a higher velocity. Out of consideration for other players, the velocity should be decreased when the range is low.