Cone-tainers System consists of individual, cone shaped cells that can be rearranged within each tray. Cells made of low-density plastic good for 3-5 uses; 1.5" dia top, 8" deep, are tapered, not free-standing without tray. Interior ribs prevent root spiraling. Only use with 1' x 2' tray, which is made of durable polystyrene, holds 98 cells, will last 8-10 years, is partially vented on the surface to provide more air flow between cells, and has locking corners for easy stacking and storage. Cells and Support Trays are ordered separately.