Clean and safe feeders. Easy for your customers. Healthy for the birds. Toxic mold in the feeder can be harmful to birds and people. Avoid it with Feeder Fresh. Re-closeable blue bag. Perfect for give-aways. Same size as our current trial size bottle. Fights rain, condensation, leaks and keeps feeder fresh. To use: Start with a clean feeder, and pour a 1/4 to 1/2 inch layer of Feeder Fresh on the bottom of your feeder. Sprinkle product on top of seed when you fill the feeder. Repeat as needed each time you fill or maintain your feeder. For wild birds only, not domestic birds.