No batteries or electricity needed, plug and use. Material: Plastic Size: 17.5cm/6.89inch Description: - No batteries or electricity needed, plug and use. - This water level gauge is suitable for flower pots. It can display the water level to remind you when to water. - When the pot is empty, the buoy of the water level gauge will be at the bottom. On this note, pull up the water level and water plants through the hole. - Simply insert the level into the soil, and it will help your plants grow healthy and strong. - An ideal tool for indoor and outdoor use. Specification: - Material: Plastic - Size: 17.5cm/6.89inch Color: White Package Includes: 5pcs of Water Level Note: Don't pour too much water, it's better to keep the water level below the top mark.