Made of fabric woven with silver thread to reduce high frequencies. It can be used to wrap Wi-Fi devices or as a bag for smartphones and other devices, with a drawstring closure featuring a plastic stopper (see photo 5). It's large enough to be worn over the head. *The item in the photos is my personal item of the same product. A new one will be sent to you. Size: 42cm (height) x 40cm (width) x 18cm (depth) Material: 100% silver (silver fiber) Effective Range: High frequencies from 3MHz to 38GHz Washing Instructions: Hand wash in water and hang to dry. Frequent washing is not recommended. Notes: The silver will tarnish over time, but this does not affect its effectiveness. ● About the Photos Photo 2: High-frequency value of a Wi-Fi device without any protection. Photo 3: Wi-Fi device with this product covering it. Photo 4: Wi-Fi device wrapped in this product. When using this product (photos 3 and 4), you can still use the Wi-Fi device as usual if it's in the same room. There will be no significant reduction in communication speed. Normally, Wi-Fi devices emit very strong radio waves to reach as far as possible. By using this product, you can weaken the radio waves within the room where the Wi-Fi device is located. As a result, the radio waves will not reach distant locations (such as the next room).