In fact, American defense and aerospace firms reap substantial benefits from U.S. aid to Israel, for it guarantees them a $1.35 billion captive market each year. Out of $1.8 billion in grants, then, Israel receives about $450 million in cash that can be converted into Israeli currency and used either to purchase Israeli-made military products or develop weapons (such as the Arrow anti-missile system). Steven L. Spiegel, a professor at the University of California in Los Angeles, points out that Israel performs invaluable services by testing and developing weapon systems for the United States, improving American-made equipment, and providing crucial intelligence information.11 Moreover, Spiegel argues that Israel's use of American-made arms not only saves the United States money but earns it more: For example, after Israel's much advertised successes with U.S. weaponry in the 1969-70 War of Attrition and the 1982 war in Lebanon, U.S. arms sales worldwide in 1972-82 nearly tripled, from about $6.8 to $19.6 billion in constant 1982 dollars.12 And while of course it does not wish for wars to occur, the United States gains valuable information by seeing its arms perform against those of Israel's enemies, lessons that "cannot be purchased, developed, or simulated."13