The TOTO NEOREST 1.28 or 0.9 GPF Dual Flush In-Wall Tank Unit is designed fro use with the NEOREST AC or EW wall-hung toilet and top unit. The in-wall unit provides you with the opportunity to save up to 9 inches of floor space within your bathroom. The NEOREST in-wall tank unit is auto flush capable and provides a dual flush option for the right amount of flush for the required job. You can select between a 0.9 or a 1.28 gallons per flush with a push of a button. The harness of the NEOREST in-wall tank unit allows you to select a mounting height of 15 to 19 inches. This provides the opportunity for you to establish a comfortable bowl height for a wide array of individuals. The in-wall unit can support up to 880lbs when installed properly. The kit includes a copper water supply line and a 2” x 6” polyethylene waste outlet for installation within a 2” x 6” stud setting. If you require installation within a 2” x 4” setting, you have the option to purchase TOTO’s 2” x 4” PVC outlet kit (THU343). The NEOREST toilet bowl, top unit, and push button plate are sold separately.