A gravity hood is a type of laboratory equipment used to protect laboratory personnel from hazardous materials. It is a sealed, enclosed unit with a fan that draws air from the outside, through a filter, and into the hood. The air is then drawn down into the hood and out through a vent. This creates a downward air flow that pulls hazardous materials away from the user and towards the filter. This helps to reduce the risk of exposure to hazardous materials and also helps to reduce the spread of contaminants. The gravity hood is a great way to ensure safety in the laboratory and should be used whenever possible.