A helmet light mount is a small apparatus that is used to hold a flashlight

Flashlight

A flashlight is a hand-held electric-powered light source. Usually the light source is a small incandescent lightbulb or light-emitting diode...

 to a hard hat

Hard hat

A hard hat is a type of helmet predominantly used in workplace environments, such as construction sites, to protect the head from injury by falling objects, impact with other objects, debris, bad weather and electric shock. Inside the helmet is a suspension that spreads the helmet's weight over the...

. When working in dark construction zones, workers find it necessary to use a light to see what they are doing. The mount device frees their hands to continue working rather than being required to hold the flashlight. The mount is normally put on one side of the helmet

Helmet

A helmet is a form of protective gear worn on the head to protect it from injuries.Ceremonial or symbolic helmets without protective function are sometimes used. The oldest known use of helmets was by Assyrian soldiers in 900BC, who wore thick leather or bronze helmets to protect the head from...

, but since this can cause the helmet to tilt to one side, some users may prefer to wear two mounts in such a way as to counter-balance each other. This is more of a personal preference and is not strictly necessary.