This is a Hubbell TayMac ML500G 1-Gang Weatherproof In-Use Cover in gray. 

• Expandable Design: The cover expands from 1 inch to 3 inches deep to accommodate plugs while in use. 

• Durable Material: It is constructed from high-impact polycarbonate and synthetic neoprene rubber that resists cracking and deterioration in sunlight. 

• Versatile Fit: The cover features a Universal Fit Adapter System (U-Fast) offering 16-in-1 configurations for GFCI, duplex, or switch outlets. 

• Easy Installation: A patented Quick-Fit keyhole mounting system allows for installation in under a minute. 

• Safety Rated: It is Extra Duty rated, NEMA 3R compliant, and UL listed for wet and damp locations.