A war reserve stock (WRS), also known as pre-positioned stocks, is a collection of warfighting material held in reserve in pre-positioned storage to be used if needed in wartime. They may be located strategically depending on where it is believed they will be needed.[1] In addition to military equipment, a war reserve stock may include raw materials that might become scarce during wartime.[citation needed] According to this definition, storage such as the Strategic Petroleum Reserve may be considered a war stock.[2]