The TOTO DuoFit in-wall 0.9 and 1.6 GPF Dual Flush Tank System with Copper Supply Line provides you with the opportunity to save up to 9 inches of floor space within your bathroom. The DuoFit provides a dual flush option with TOTO’s Dual-Max. Dual-Max makes conservation easy, allowing you to choose the right amount of flush for the required job. You can select between a 0.9 or a 1.6 gallons per flush with a push of a button. The DuoFit harness 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 arrives ready to be installed within a 2” x 6” stud setting. If you require installation within a 2” x 4” setting, you will need to additionally purchase TOTO’s 2” x 4” PVC outlet kit (THU343). This comes with a copper supply and a 2” x 6” polyethylene waste outlet. If you want to enhance the toilet you choose with a WASHLET bidet seat, there is a pre-attached copper supply built into the system. You will additionally have to purchase a TOTO WASHLET Connection Kit to complete your WASHLET install (THU468). This DuoFit requires the toilet bowl and flush push plate to be purchased separately. Compatible wall hung toilet bowls: CT486FG, CT418F, and CT418FG