Zurn 2-1/2" to 6" Iron Air Gap for 375, 475

2-1/2" to 6" Iron Air Gap for 375, 475 Designed for use with 1/4" thru 10" Model 975XL, 375, and 475 Reduced Pressure Principle Backflow Preventers on horizontal or vertical installations. Device is necessary when installing a drain line and can be mounted to the body. (Drain line can be any standard piping material.)