The low cover, is either for the black 80 micron nylon filter or the yellow 30micron polyester felt filter. As ian says, the black is used in humid and/or cold environment - the yellow for dry dusty ones. The taller cover is for the high polyester filters for very dusty environments, such as clearing after a forest-fire, cutting by a beach, quarries and so on. These filters are not made of paper but polyester and should be cleaned using soap and water. There are special filters which use a main filter of paper and a secondary of foam but they are only used on the cutter-saws, cutting in stone etc...
/Ola