5" Ceramic Self Water Pot Tropical Red - 3.5" opening Inner size for planting is 3.5in opening X 3in deep. Overall size: 5in x 3.75in H. Fits a 3 to small 4 inch potted plant. Fill the bottom portion half way with water and place planted inner pot inside. Water will soak through unglazed inner pot keeping soil moist. This colorful ceramic planter cuts down watering frequency and plants stay healthy and happy for days without much attention. This ceramic planter is high temperature fired. Unlike plastic pots, it won?t fade or crack in the sun. Ideal for indoors or outdoors (above freezing). See description below on planting instruction