Here's an excerpt from the product description from the HP website: This product uses fabric that is breathable and has a UPF rating of 50+, the highest level of UV protection. Taping is applied to prevent rain from entering, and it is water-repellent. The size can be adjusted with a belt. 【Recommended Points】 ・Uses fabric with a UV cut rate of 90% or more and UPF 50+. ・The fabric has a three-layer structure: a water-repellent finish on the surface, a breathable fabric in the middle layer. 　Waterproof tape is applied to the inside to prevent rain from entering, making it suitable for use regardless of the season or climate. ※Brim length: 7.0cm Please feel free to comment if you have any questions.