An outlet gate/gate assembly having a trough section having opposing slanted sheets, and an end sheet at ends thereof, the trough section defining a trough, and each end sheet providing a discharge opening fluidly connected with the trough; and an end tube/end adapter assembly fluidly connected with each end sheet, the end tube/end adapter assembly comprising an end adapter, an outlet cap, and an end tube seal/end adapter gasket, the end tube seal/end adapter gasket positioned between the end sheet and the end adapter or within the end adapter, wherein the end tube seal/end adapter gasket comprises a base plate and a primary/main flap, the base plate defining a discharge opening, and the primary/main flap biased to, when closed, completely cover the discharge opening.