Polyester swim caps are a type of swim cap made from polyester material. They are a popular choice for swimmers who want a lightweight and durable cap that can withstand frequent use in the pool.

Polyester swim caps are known for their smooth and comfortable feel, making them an ideal option for swimmers with sensitive skin. They are also very stretchy, which means they can fit a wide range of head sizes and shapes.

Another benefit of polyester swim caps is that they are generally more affordable than other types of swim caps, such as silicone or latex. They also tend to be more resistant to chlorine and other pool chemicals, which means they can last longer before needing to be replaced.

However, one downside of polyester swim caps is that they allow the water to come straight through so while they will work to keep hair out of the face when swimming, they won't keep the hair dry. Additionally, they may not provide as much insulation or warmth for swimmers in colder water temperatures.

Polyester swim caps are a great option for swimmers looking for a durable, comfortable, and affordable swim cap that can withstand frequent use in the pool.