Today's laser tag systems work on the following, where a sensor pack that is attached to the pack, your pack is wireless and reports back to a master computer that tabulates the amount of times that you were hit or hit someone else. When you pull the trigger, the infrared LED lights up, but the infrared can not be seen by humans. The packs sensors are actively looking for Infrared lights, if you are in range your pack will register the hit. the part of the laser tag beam that you can see is sometimes a laser or a very bright focused red LED. 