Complex sentence: Airsoft guns with muzzle energy below 3 joules (muzzle velocity 173.2 m/s for 0.20 g projectiles) are legal, not considered weapons and do not require any permission.
Split into simpler sentences: Airsoft guns with muzzle energy below 3 joules (muzzle velocity 173.2 m/s for 0.20 g projectiles) are legal. They are not considered weapons and do not require any permission.