This magic screen will protect you from other users peeping on your mobile phone screen. The protection screen is selling at $3 USD in Korea per piece. It block any vision more than 30 degrees.

Magic Screen is Privacy Protection Film as well as blind method film which has a visual angle control function. When you attach this film to your LCD screen of mobile phone or computer monitor, you can enjoy mobile banking, e-mail or game at public place without being overlooked by other people because this film can be seen from the front but there is not a possibility of seeing the screen from the side, an angle of more than 30 degrees.  

If you want even more, it can show a print-coating Character or Logo instead of a all black screen to other people.