Adjustable valve: The flow rate can be controlled. The plant watering device with regulating valve can control the drip speed from 0 to 60 seconds/drip, and the continuous drip lasts 1 to 15 days. Adjust the valve only to meet your needs without complicated setup steps. Save time and water. Simple and practical: Installed without any tools, just drill a few holes in the bottom of the bottle or cut the tail of the bottle so that the air can 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, old leaves just turn yellow and fall off, but if new growth yellow , it may be an indication of overwatering or under water. WarningCompatible with all 1.1inch/2.8cm inner diameter, fits most water bottles drinks, not suitable for mineral water and purified water bottles. (Measure the inner diameter of the bottle including thread size before installation) Product size: 8 x 3.5 x 25.5 cm. Product color: green, blue Delivery quantity: Eight pieces