In addition to expressed and delegated powers, presidents have claimed a third source of powers that are not expressed or implied in the constitution and are known as

It is the Inherent Powers.

Inherent Powers are not explicitly mentioned in the constitution but these are reasonable powers that are delegated to the President and the Congress.  These powers are needed by the President in some situations to effectively do his job and responsibility. An example of this situation is when there is a national emergency that requires quick actions.