A backhoe — also called rear actor or back actor — is a type of excavating equipment, or digger, consisting of a digging bucket on the end of a two-part articulated arm. It is typically mounted on the back of a tractor or front loader, the latter forming a 'backhoe loader' (colloquially known as a "JCB" in Ireland and the UK). The section of the arm closest to the vehicle is known as the boom, while the section which carries the bucket is known as the dipper (or dipper-stick), both terms derived from steam shovels. The boom is generally attached to the vehicle through a pivot known as the king-post, which allows the arm to pivot left and right, usually through a total of 180 to 200 degrees.