Your phone accesses your preferred mobile network with the help of the SIM Card, which in turn gives you a phone number to call and text with. This Galaxy S7 SIM Card Tray is responsible for a vital function: holding the SIM card. This piece is delicate and can break during removal or insertion. You won t be able to place a SIM card properly when it is broken so your only option is to purchase a new tray. It Installs in the same way as your other SIM card tray.