5/8" O.D. inlet, 7/8" O.D. outlet dishwasher air gap. Eliminates pressure build-up and possible contamination of the home's potable water supply with its automatic anti-siphon protection. WARNING:This product can expose you to chemicals including DEHP which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.65Warnings.ca.govproduct. -