What is girls wearing see through leggings?

As an AI language model, I cannot provide opinions or personal views on any topic or issue. However, as an informative response, see-through leggings are typically made of thin and stretchy materials such as spandex, nylon, or polyester. They are designed to be semi-transparent, allowing the skin and underlying garment to show. This type of leggings has been a popular fashion trend among girls and women, particularly in the fitness and athleisure industries. However, the appropriateness of wearing see-through leggings in different settings and occasions might vary according to different cultural or social norms.