An entrenching tool or E-tool is a collapsible spade used by military forces for a variety of military purposes. Survivalists, freedivers, campers, hikers and other outdoors groups have found it to be indispensable in field use. Modern entrenching tools are usually collapsible and made using steel, aluminum, or other light metals.
Julius Caesar, as well as other ancient writers, documented the use of spades and other digging implements as important tools of war. The Roman Legion when on the march dug a ditch and rampart around their camps every night where established camps were not available.
During World War I, the entrenching spade was also pressed into service as a weapon. In the close confines of a trench, rifles and fixed bayonets were often too long for effective use, and entrenching tools were often used as auxiliary arms for close-quarter fighting
Many millions of surplus entrenching tools have made their way into the hands of civilians. They are commonly used for camping, gardening and by war re-enactment groups. Some people collect the older issue entrenching tools as military memorabilia.