Anti-theft Car Key Case Phone Blocking Radio Waves Faraday Box Faraday Cage 20cm x 11cm The case protects electronic devices from mechanical damage, but it also has a number of other functions. First of all, it blocks the signal, making the phone out of range, has an anti-radiation function and prevents the demagnetization of data carriers and the loss of files stored on them. Specification: Size: 20 cm long and 11 cm wide Compatibility Due to its size, the case can accommodate not only keys or small data carriers, but also mobile phones with a maximum screen size of 6 inches. You can also fit GPS navigation, a driving recorder, a portable hard drive (provided it is the right size). Dual operation Placing the mobile phone in the outer layer can reduce the radiation of the mobile phone part, and it does not affect the connection of calls and text messages by the mobile phone; Putting the mobile phone in the inner layer and covering it to not only prevent electromagnetic radiation and protect human health, but also block the phone signal to be in a "sleep" state. In this case, outsiders cannot connect with you. When you place your phone in the inner layer: If your mobile phone has not activated the call reminder function, you will see a message when you call that you are unavailable. If your mobile phone has the call reminder feature turned on, when someone calls, they will hear you say that you are unavailable, and you will call you back when you are free. When you take your phone out of the protective bag, you'll receive a text message reminding you to make a call. After placing the phone in the inner layer for about an hour, the mobile phone will turn off if it does not receive a signal for a long time. This applies to all standard devices – they start working when they are taken out of the case.