A SIM card, or Subscriber Identity Module card, is a smart card that stores identification information that pinpoints a smartphone to a specific mobile network. SIM cards are used in smartphones globally and are a device that makes it possible to identify and authenticate a user as a unique mobile device owner. They contain data such as user identity, location, phone number, network authorization data, personal security keys, contact lists, and stored text messages. SIM cards allow a mobile user to use this data and the features that come with them. Without a SIM card, some phones would not be able to make calls, connect to internet services such as 4G LTE and 5G, or send SMS messages. SIM cards are removable and transferable to other phones, and they must be placed into a GSM phone to access the local mobile network to place or receive calls or send texts. SIM cards are also an important personal identifier for a phone, its phone service, and related user activity, acting as an ID badge for the service user and attached device.