Genuine Gerber TC-28-990-09 tank lid. This lid is in biscuit. This lid is for Gerber 12" rough in tanks. The rough end is the distance from the wall to the center of the floor bolt. This lid is NOT for insulated, or dual flush tanks. TC-28-990 only fits the single flush tanks. The "rough in" is the measurement from the wall behind the toilet to the center of the bolt that connects the toilet to the floor. Before placing your order we highly recommend verifying the rough in to save money in case of a return.