An material that lets electric charges flow through it easily is called a conductor. Conductors have low resistance to the flow of electric current, meaning that electrons can move through them with relative ease. This is due to the presence of free electrons in the material, which are not bound to any particular atom and are therefore able to move freely when an electric field is applied. Some examples of good conductors include metals such as copper, aluminum, and gold, as well as certain solutions and electrolytes.