These waterer adopt gravity fed system, and the cup will automatically refill fresh water to half cup, no overflow. So your poultry can drink clean water as long as there are water in the bucket. This auto waterer is suitable for chicken, duck, goose, turkey, quail, rabbit and so on. 2.5 inch diameter cup allows chicken to dip their beaks in the water when drinking. The parcel comes with 4 or 6 or 12 * water cups. Just make use of a bucket, then you can DIY auto poultry waterer in minutes. Please prepare the electric drill machine and bucket yourself. Not suitable for high pressure pipe. The water cup has rubber washer to stop the water from leakage. Please tighten the screw and check for leakage before use. Just fill the bucket full, then these water cups will supply drinking water automatically. It can reduce your workload and prevent water waste. Please do not forget to refill the bucket.