The Horizontal Drain Adaptor is used to adapt to various exhaust fans in the industry. For best results, grease should be directed to fall into the middle of the filter/pillow. The adapter allows grease to get past the fan base to hit into the grease containment system. Designed to help direct grease to the rack system. Connects to "U" shaped drain spout to add length for drainage. Made to allow PVC Hose connection for additional length (hose not included). 1-1/4 Inch Diameter NOTE: in some cases, hose extensions are needed. These adapters are also used to plumb the DRIP LOC Pail Filter System. WARNING : This product can expose you to chemicals including Cobalt Metal Powder and 1,3,5-Triglycidyl-s-triazinetrione, which is known to the State of California to cause cancer. For more information, go to www.P65Warnings.ca.gov .