1)Our own patent 2)could stack one by one ,save space ,easy set up 3)both ... it Specifications1)Our own patent 2)could stack one by one ,save space ,easy set up 3)both ... 3pcs of pot ,3pcs self-watering grid , one bottom tray, one pcs of steel chain -----usually for supermaket B) Stacking ... the pot one by one to higher six or more pcs ---- ...