Keep these covers closed during operation to completely shield outlets and plugs from rain, snow, and wet indoor conditions. A sealing gasket keeps out dust and moisture. These corrosion-resistant covers are rated NEMA 3R for protection from falling liquids and light splashing. They meet OSHA 29 CFR 1910.1200, which means they wont release more than trace amounts of hazardous chemicals and wont pose a physical hazard or health risk to employees. Covers for two devices can be modified for any combination of devices. Expandable covers can be extended to cover greater depth.