Need something to complete your Dumb and Dumber Costume this Halloween? This Dumb And Dumber Hat is the perfect accessory for your Harry costume because it adds style and flare. This Dumb And Dumber Hat comes in one size that fits most. The Dumb and Dumber Hat is about 5 _" high and is styled like a hat from the late 19th century. Everyone knows that accessories can make or break a costume, so this year make it happen.