A revolver is a type of gun. Revolvers are repeating firearms with a cylinder that spins. Revolvers have several chambers each holding one cartridge. Most are handguns, but other types of weapons also use revolving cylinders. They are also called revolving guns, though "revolver" is used far more often. The first revolvers date back to late 1500s in Europe. It was not until the 1700s or 1800s, however, they became affordable. Revolvers are sometimes used by law enforcement agencies. On some occasions, these guns can be reset by one hand, then loaded with the other.