A sun helmet is a type of protective headgear that is designed to shield the wearer from the sun's rays. The term 'sun helmet' can refer to three different types of headgear: TOPEE, TOPI, and terai. A TOPEE is a lightweight, brimmed hat made of straw or felt, typically worn in tropical climates. A TOPI is a traditional African hat made of cloth or leather, often with a wide brim. A terai is a type of pith helmet, which is a lightweight hat made of cork or pith, typically worn by military personnel in hot climates. All three of these types of sun helmets provide protection from the sun's harmful rays.