Many mobile phones on the market have a built-in small slot that allows us to tie a strap to the terminal, however, the iPhone has never offered that possibility until today since the guys at USB Fever have designed a plug that is installed in one of the gaps that are left free when removing the screws from the bottom and that allows us to add a strap to the iPhone 4.
The kit with the screwdriver, plug, strap and ring costs $ 10 and you can buy it directly from the manufacturer's website.
Source: applesphere