The non-caustic, non acidic, and no bleach cleaner is safe for cleaning all outdoor surfaces the Wet and Forget outdoor cleaner can be used for eliminating mold, moss, mildew, lichen, and algae. Included with (4) Gallons the Wet and Forget has an unlimited shelf life requires no scrubbing, no rinsing, and no pressure washing. Includes 4 bottles of 1 gallon outdoor Wet and Forget cleaner. This item is not available for sale to California.