ZFE Most Easy-Use Vacation Plant Waterer, Set of 8 Ceramic Watering Stakes, Perfect for Vacation Plant Watering and Drip Irrigation Watering, Self Watering Spikes for Indoor&Outdoor Use Pack of 8Pcs Plant Ceramic Vacation Holiday Watering Spikes Nanny Self Water Stakes Nozzles Plant Ceramic Vacation Holiday Watering Spikes Nanny Self Water Stakes Nozzles. The probes are made of ceramic material that will keep the watering at a constant speed. Please note that the watering speed is decided by different soil density, plant water absorption ability and other factor. It's recommended that you buy the product one week before you go out for a trip so that you can test the watering speed. eight Spikes for one pack. The quantity of 1.5lt water may last a period of 20 days. This watering spikes have two diameter bottle cap. The bigger one's diameter is about 1.89 inches, the smaller one is about 1.1 inches. Instruction: Firstly, prepare a bottle to fill water. Secondly, connect the bottle mouth to the connector. Thirdly, insert the water probes into the soil of the flowerpot, near to the plant's root.