Perlite #8 X-Large & Bulky 4 cu.ft. bag [Case of 15]Case Quantity is: 15 No 8 Perlite features EXTRA LARGE and BULKY coarse particles which maximize nutrient uptake, drainage, and aeration and help prevent water rot at the root level. Perlite can be used as a stand alone medium in drip systems or as a mix in element with other growth mediums, and works especially well for plants that need excellent drainage.