Stay hydrated and keep your plants happy with these 3Pcs Adjustable Drip Automatic Self Watering Spikes. Made of strong PP plastic, these spikes are designed to fit standard water bottles of 28-30 mm openings. The stepless speed regulation adjusts the dripping speed with a simple twist. With a dimension of 17.5*5 cm, enjoy up to 22 days of delivery with this package of three.