"CocoPro™ cubes contain thoroughly washed and buffered coco fiber, pith, and husk for a consistent ratio of air and water throughout each cube. This high-performance blend delivers oxygen to plant roots while retaining moisture and nutrients – giving you more control over your fertigation regimen. The breathable fabric cover promotes air/gas exchange for increased root-zone oxygen levels, provides excellent water drainage for faster dry-down times, and encourages natural pruning and branching for a healthy root system.