The term select-fire is used to describe firearms that have the capability to fire in both semi-automatic and automatic modes. On an M4 for example, the shooter uses the safety switch to select semi-automatic or automatic fire modes using their thumb. Some select fire weapons are designed to fire in semi-automatic or in a three-round burst mode. These types of firearms are heavily regulated and require a detailed licensing procedure and tax payment for someone to own one. They must be documented as pre-1986 transferable and are subject to a detailed licensing procedure. Even then, they are not legal in some states regardless of this status.