The Mansfield genuine 2036-1212 is designed for the Mansfield 1.28 gallon per flush Summit models. This would include the models 387, and 377. The flapper on this flush valve is not offered seperately. It is hard plastic, so usually it will not go bad, or break, but the rubber red seal on the bottom side of the flapper is offered seperately. It is part number 630-0030.
