Diablo Smart Tank Easy Switch Plate Waste Water for 230mm & 305mm High Tanks Black water tank hatch with gasket, 2 inlet/outlet, 1 1/2" thread and 1 inlet/outlet with 1" thread. Included: no. 2 - 90° fittings, 38 mm diam. thread 1 1/2" no. 2 - 90° fittings, 25 mm diam. thread 1 1/2" no. 1 - 90° fitting for 25 mm diam. vent, thread 1" no. 1 - 90° fitting for 20 mm diam. vent, thread 1" Sizes: Switch Plate Waste Water for 230mm High Tanks - (4060074) Switch Plate Waste Water for 305mm High Tanks - (4060075)