Adjustable valve: The flow rate can be controlled. The plant watering Device with control valve can control the dripping speed of 0-60s/drip, and the sustained drip lasts for 1-15 days. Only adjust the valve to Meet your needs without complicated setup steps. Save time and water. Simple and Convenient: Installed without any tools, just drill some holes in the bottom of the bottle or cut the tail of the bottle to keep the air flowing. Multi-Scene Application: vegetables, potted plants, houseplants, water plants day-to-day, patio plants, herbs, hanging baskets, desk pots, hanging plants, outdoor gardens, small tree, shrubs. WarningCompatible with all 1.1 inch/2.8cm inner diameter, suitable for most beverage bottles, not suitable for mineral water and purified water bottles. (Measure the inner diameter of the bottle including the thread size before installation) Product Description Length of stake:5.31inch/13.5cm The Self Watering Spikes are long enough to hold securely on pots. Inner diameter1. 1inch /2.8cm Compatible with all 1.1 inch/2.8cm inner diameter, suitable for most beverage bottles, not suitable for mineral water and purified water bottles. (Measure the inner diameter of the bottle including the thread size before installation) Self Watering Accurately control the flow and give appropriate amount of water for different plants and flowers. How to use Step1, Tighten the knob on the control valve. Step2, Place the control valve into the self watering spikes and tighten it. Step3, Put the watering device in the plastic bottle Step4, Make an opening in the bottom of plastic bottle. Step5, Insert the self watering spikes into the pot and shake it slightly to check its stability. Step6, Loosen the slow release control valve switch on the regulating valve according to the irrigation needs.