Itis good at water discharging, storing and adjusting. It is of good durability and for heavy load. It is light and good for room heat insulation. Its special design can guarantee the oxygen supply for the plants. It is simple and cheap in construction and maintenance. The boards can be interlocked at your own disposal and is an indispensable basic material in the gardening project. This product has been widely used on roof, underground parking lot, urban plaza, golf field, sport field, partition, wastewater treatment plant, balcony, etc. for water drainage.