Raise your crawl space dehumidifier with either a set of 3" risers or a set of 5" plus 3" risers. 3" riser sets come with four risers total for each footing of the crawl space dehumidifier. Our set of 5" risers with 3" risers come with eight total risers giving you the ability to raise your dehumidifier 8" above the crawl space floor.