Combination louvers incorporate front stationary drainable blades and integral rear adjustable blades, all within a single frame, to provide excellent protection against water penetration when open and positive airflow shutoff when closed. The drainable blade design utilizes rain gutters that divert collected water through concealed side downspouts and out the sill, effectively preventing water from infiltrating the space when the blades are in the open position. Low torque, concealed linkage blade control can be operated manually or with a variety of factory mounted electric or pneumatic actuators to provide tight shut-off when desired. Suitable for use in exhaust and low to medium velocity intake applications. Available in channel or flanged type frame.