A Company is a Military Unit. It usually has 80 to 250 soldiers. A company is usually led by a captain or a major or another officer. Most companies are comprised of three to six platoons, although the exact number may vary by country and type of unit (infantry, armor, etc.). Several companies are grouped to form a battalion or regiment. In the United States military, before the September 11 attacks, companies trained in conventional warfare for basic offensive and defensive operations.[1] Since then companies have had to train for a much wider variety of tasks.[1] These may include humanitarian aid missions, providing security and maintaining order in an area.[1] Different elements in an army may assign different tasks or have different names for a company. For example, a corps of engineering such as the Royal Engineers use the term squadron for a company.[2] In artillery units (as well as some other examples), the name "company" may be replaced by the name "battery" or “troop”. There is one specialized Company in the United States Army. It is the 911th Technical Rescue Engineering Company.