ADJUSTABLE VALVE - Automatic watering spikes with drip rate control valve for 0-60 seconds/drip. The drip rate can be adjusted according to the amount of water your plants need. It can take care of your plants for 1-15 days. ECO-FRIENDLY & DURABLE- Self-watering spikes are made of high-strength plastic, heat and cold resistant, not easy to break, can be installed and used indoors and outdoors, and can be reused. Plastic bottles can be recycled to reduce waste and protect the environment. EASY TO USE - No tools are required for installation. Drill a few holes in the bottom of the bottle or cut the end to keep air flowing, then adjust the control valve and insert the automatic watering spikes into the soil. It is an essential gardening aid. WIDE APPLICATIONS - The automatic drip irrigation watering device is suitable for all 1.1 /2.8cm ID beverage bottles, works with most beverage bottles such as Coke bottles, soda bottles, etc. (Measure the inner diameter of the bottle, including thread size, before installation) INDOOR AND OUTDOOR USE - Adjustable plant watering spikes are suitable for all indoor and outdoor plants such as vegetables, potted plants, hanging baskets, table pots, hanging plants, outdoor gardens, small trees, shrubs, etc.