What are the categories of sunglasses?

　　Sunglasses are UV resistant glasses that are typically used for outdoor activities. According to different designs and functions, sunglasses can be divided into several categories.

　　Polarizer: It can block reflected light and reduce eye fatigue. Suitable for use in water sports, skiing, mountain climbing and other activities.

　　Lens color classification:

　　Gray lenses: the most basic sunglasses suitable for most outdoor activities.

　　Green lenses: suitable for occasions with weak solar intensity, with good color reproduction.

　　Brown lenses: suitable for occasions with strong reflected light, such as beaches, mountains, etc.

　　Red or pink lenses: suitable for days with haze or strong sunlight intensity, can increase contrast.

　　Material classification:

　　Glass lenses: Good scratch resistance, but heavy and prone to breakage.

　　Resin lenses: lightweight and comfortable, but have poor scratch resistance and are prone to scratching.

　　PC lenses: Strong impact resistance, suitable for use in extreme environments, but poor scratch resistance.

　　Mirror frame classification:

　　Metal frame: Heavy in weight, but with good toughness.

　　Plastic frame: lightweight and comfortable, but with poor toughness.

　　In addition to the above categories, sunglasses also have some special functions, such as anti sandstorm, anti fog, night vision, etc. Therefore, when choosing sunglasses, it is necessary to choose according to one's own needs.