Some items can be worn under a hard hat. The use of a hard hat doesn’t mean other headgear can’t be used. Bandanas, head warmer, and hoods can be beneath a hard hat. For example, in a cold season, the ventilation system of a hard hat may result in too much cold air to the head. To avoid this, a head warmer can be worn beneath the hat. Nonetheless, the head must not be too thick such that it affects the suspension system that helps keep the hard hat firmly on the head.