HeavyDuty Beathable Tight Mesh Winter Top Air Conditioner Cover - 40x30 - Gray Provides top protection during winter with its tight breathable mesh and does not cause rusting to your ac unit. This cover is NOT waterproof. We also sell Premier waterproof tops Highly resistant to sunlight, mold, mildew, and temperature extremes. 5 year manufacturer's waranty. 100 satisfaction guaranteed