Atlantic Water Gardens REDESIGNED EcoBlox Water Matrix allows for 31.5 gallons of water storage for pond-free applications, bog filters, and water harvesting. Holds 3x more water than traditional gravel basins. 8-panel construction for exceptional strength. 1/2" x 3/4" hole size can be used with smaller gravel. New slide-lock connection system. 16"W x 27"L x 17.5"H.