AG200-004 Air Gap International Dual Air Gap for Double Drawer Dishwasher A dishwasher air gap is a critical component in maintaining a safe water supply. It prevents contaminants in the sink from flowing into the dishwasher and is required by code in most states.The Amerigap brand dual dishwasher air gap provides many advantages over other air gaps available on the market and ensures safety and peace of mind that your water supply is clean.A common misconception is that a “high loop” (routing a drain line above a sink’s flood level, for instance) and a wye connection will provide the same function as an air gap; this is not true, because the continuous connection between dishwasher and drain line still will allow back-flow through siphoning.This air gap is easy to use and legal to install in any state. The AG200-004 air gap is listed by UPC and tested for compliance with IPC and NSF standards.