Airsoft guns are spring, electric, or gas powered air guns that fire small round plastic pellets of either 6 mm to 8 mm in diameter, also known as BBs. Spring-operated airsoft guns are also known as air guns by some airsoft players. Cheap airsoft guns are often very low powered and some airsoft players use them as a starting point, these guns are great to play on grounds like a backyard.
The more expensive models are used for playing professionally, which is similar to the game of Paintball; the only difference is that airsoft game is a military simulation. Airsoft guns are similar replicas (not identical) of real firearms, but firearms or body kits are available to make the game feel more realistic, such as the M41A Rifle from the popular films. Inexpensive airsoft guns are smaller scale models, about ¾ of the actual size of a 1/1 scale; mini electrics would be a good example.
Finally, some designs are replicas of firearms that never even went into service or production yet, such as XM8 prototypes, which may be replacing the old M4’s. All the different types of airsoft guns, spring, gas, and electric, work on the same principle of compressed air to force a pellet down the gun's barrel, each one has its own unique preference.