Keypad in the context of Television remote control

A mobile device or handheld device is a computer small enough to hold and operate in hand. Mobile devices are typically battery-powered and possess a flat-panel display and one or more built-in input devices, such as a touchscreen or keypad. Modern mobile devices often emphasize wireless networking, to both the Internet and to other devices in their vicinity, such as headsets or in-car entertainment systems, via Wi-Fi, Bluetooth, cellular networks, or near-field communication.

A stored-value card (SVC) or cash card is a payment card with a monetary value stored on the card itself, not in an external account maintained by a financial institution. This means no network access is required by the payment collection terminals as funds can be withdrawn and deposited straight from the card. Like cash, payment cards can be used anonymously as the person holding the card can use the funds. They are an electronic development of token coins and are typically used in low-value payment systems or where network access is difficult or expensive to implement, such as parking machines, public transport systems, and closed payment systems in locations such as ships.

Stored-value cards differ from debit cards, where money is on deposit with the issuer, and credit cards which are subject to credit limits set by the issuer and are connected to accounts at financial institutions. Another difference between stored-value cards and debit and credit cards is that debit and credit cards are usually issued in the name of individual account holders, while stored-value cards may be anonymous, as in the case of gift cards. Stored-value cards are prepaid money cards and may be disposed when the value is used, or the card value may be topped up, as in the case of telephone calling cards or when used as a fare card.

Clamshell design is a form factor commonly used in the design of electronic devices and other manufactured objects. It is inspired by the morphology of the clam. The form factor has been applied to handheld game consoles, mobile phones (where it is often called a "flip phone"), and especially laptop computers. Clamshell devices are usually made of two sections connected by a hinge, each section containing either a flat panel display or an alphanumeric keyboard/keypad, which can fold into contact together like a bivalve shell.

Generally speaking, the interface components such as keys and display are kept inside the closed clamshell, protecting them from damage and unintentional use while also making the device shorter or narrower so it is easier to carry around. In many cases, opening the clamshell offers more surface area than when the device is closed, allowing interface components to be larger and easier to use than on devices which do not flip open. A disadvantage of the clamshell design is the connecting hinge, which is prone to fatigue or failure.

A security token is a peripheral device used to gain access to an electronically restricted resource. The token is used in addition to, or in place of, a password. Examples of security tokens include wireless key cards used to open locked doors, a banking token used as a digital authenticator for signing in to online banking, or signing transactions such as wire transfers.

Security tokens can be used to store information such as passwords, cryptographic keys used to generate digital signatures, or biometric data (such as fingerprints). Some designs incorporate tamper resistant packaging, while others may include small keypads to allow entry of a PIN or a simple button to start a generation routine with some display capability to show a generated key number. Connected tokens utilize a variety of interfaces including USB, near-field communication (NFC), radio-frequency identification (RFID), or Bluetooth. Some tokens have audio capabilities designed for those who are vision-impaired.