Sunleaves Classic Coir Brick is a compressed coconut-fiber growing medium that expands to approximately 1/3 cubic foot when soaked in water. Certified by the Organic Materials Review Institute (OMRI), this renewable resource is pH-neutral and retains air and moisture extremely well. Classic Coir is the original finely-shredded composition that growers have come know and love and is a preferred choice among African violet enthusiasts. Great for amending soil and soilless mixtures.