Oasis Ceramic Self Watering Planter - 4" Round- White One-piece ceramic! No assembly required! Eliminates over watering of plants! Easy to use, environmentally friendly and waters plants automatically for up to 30 days... Can be used with a large variety of plant types including ornamental and sensitive plants. Plants use water as needed by absorbing moisture through the clay wall. Design allows for excess water and fertilizer to run through creating proper ventilation for the root system.