The CamelBak Brush Cleaner keeps your delivery tube and reservoir clean and mildew-free. Staying hydrated just isn't as fun if you're injesting all types of bacteria. Kit includes two brushes. Reservoir brush has a radial tip to prevent puncture of the reservoir. The nylon brush works to prevent mold and mildew. A flexible spring wire cleans the CamelBak delivery tubes. The memory bristles if frazzeled, return to their original state when heated with an ordinary blowdryer.