While most combat battalions carry over half a million rounds of over a dozen different types of ammunition (for 5.56mm, 7.62mm and 12.7mm machine-guns, mortar shells, several types of grenades and missiles and so on), they also carry up to 30,000 or more batteries, of over 20 different sizes. The battery supply problem has been increasing for sixty years. During World War II, a battalion had to haul several hundred batteries for radios and flashlights. But in the 1960s, more electronic gear came into use (like night vision devices.) Now there are GPSs, range finders and a lot more radios. Unlike ammunition, batteries are dual-use. Troops will, if given the chance, use some of the more common battery types for their own electronic gear (CD players and portable electronic games being the most common current culprits.)