Cast Iron bowl has brass push-button non-siphoning water valve with built-in-fow control. Push-button watering is popular because there is no paddle to wear out or become jammed with direct, hay etc. This bowl is self-ceaning and trouble-free big enough for sows and small enough for little pigs Recommended water pressure range is 5 to 65 psi. Biwl has 3/4" male NPT connection.