A har hat is a type of helmet predominantly used in workplace environments, such as construction sites, to protect the head from injury by falling objects, debris, bad weather, and electric shock. Sometimes the helmet shell has a midline ridge. Inside the helmet is a suspension which spreads the helmet's weight over the top of the head, providing spacing between the helmet's shell and the head so that if an object strikes the head, a safety distance cushion of approximately 3cm lessens the blow.