Adjustable Valve: The flow rate can be controlled. The plant watering device with control valve can control the drip speed from 0 to 60 seconds/drip, and the continuous drip lasts from 1 to 15 days. Adjust the valve uniquely to meet your needs without complicated setup steps. Save time and water. Simple and Convenient: Installed without any tools, just drill a few holes in the bottom of the bottle or cut off the tail of the bottle to allow air to flow freely. Accurate Water Volume: Provide different amounts of water for different plants and flowers, do not become plant killers, other watering devices are too little or too much in some plants, the old leaves turn yellow and fall off, but if the new growth yellow, it may be an indication of overwatering or underwatering. WarningCompatible with all 1.1 inch / 2.8 cm inner diameter, fits most beverage bottles, not suitable for bottled mineral water and purified water. (Measure the inner diameter of the bottle including the thread size before installation) Spike Length: 13.5 cm. Inner Diameter: 1. 1 inch / 2.8 cm Compatible with all 1.1 inch / 2.8 cm inner diameter, fits most beverage bottles, not suitable for bottled mineral water and purified water. (Measure the inner diameter of the bottle including the thread size before installation) Water Volume Control Accurately control the flow rate and give the appropriate amount of water for different plants and flowers. Step 1 Tighten the control valve knob. Step 2 Insert the control valve into the self watering spikes and tighten. Step 3 Place the waterer in the plastic bottle. Step 4 Make an opening at the bottom of the plastic bottle. Step 5 Insert the self-watering spikes into the jar and shake gently to check its stability. Step 6 Loosen the slow-release control valve switch on the control valve according to the irrigation needs. Notes: 1. Make sure there is a hole in the bottle or the bottom of the bottle is cut off. Without air pressure, no water will come out for irrigation. 2. Adjust the water flow to the maximum value before each use. Make sure there is no air in the spray nozzle. Then slowly adjust the water flow. 3. After adjusting the flow rate and burying the outlet of the irrigation system in the ground, the flow rate is the most stable. Color: Blue, Green Package Includes: / 10 * Blue Automatic Flower Watering Device 10 * Green Automatic Flower Watering Device 1.For manual measurement, please allow 1-2cm error. 2.The color may have a little difference due to lights, screens, etc.