M-101526-F33 Sloan Flushmate® Complete Replacement System for FM III 503 Series Two-Piece ToiletThe Sloan M-101526-F33 Flushmate System is a complete pressure-assist flush system for 503 series tanks. It ONLY fits porcelain manufacturer Gerber 10” rough-in fixtures. (“Rough-in” refers to the measurement from the wall behind the toilet to the bolts that hold the toilet to the floor.)The system includes:Vessel-1.6 gpfLower Supply NutTank NutFlushmate-to-Tank GasketTank-to-Bowl GasketNOTE: The Flushmate® system is not designed to work as a replacement or upgrade for a conventional toilet. This unit is intended to be sold as a replacement system for an existing Flushmate®.