Geberit Duofix In-Wall System For Wall-Mount Toilets 2X6 Construction 1.6/0.8 GPF - 111.335.00.5Geberit Duofix In Wall System For Wall Mount Toilets 2x6 Construction 1. 6 0. 8 GPF 111. 335. 00. 5 The Geberit Duofix in wall carrier system with Sigma concealed tank is designed for 2x6 construction, offering reliable performance, water efficiency, and design flexibility for wall hung toilets. Features Compatible with most wall hung washdown toilets from leading ceramic manufacturers Dual flush system with 1. 6 0. 8 GPF for significant water savings