What is a "Trident" from the autobiography, The Heart and the Fist?

A golden Navy Trident is given to each SEAL upon graduation from Advanced Training. The Trident consists of an anchor, symbolizing the Navy, its roots, and its mission of power projection and peace; the trident, symbolizing a SEAL’s connection to the sea; the pistol, representing the SEAL’s capabilities on land; and the eagle, the nation’s emblem of freedom and symbolic of the SEAL’s air abilities. Eric is both honored and thrilled to receive his Trident and to be made a SEAL.