But it will give you 10 hours of talk time on its replaceable AA battery, which will keep for 15 years if the phone isn't used.

Meant for use in emergencies and natural disasters, this phone is called the SpareOne. It has only the bare necessities - a number keypad, dial and hang-up buttons, and basic volume control. It also has a small flashlight and an "emergency call" button that automatically dials the local authorities when pressed.

The device is on display at the Computex exhibition, running this week in Taiwan. It is very light and easy to use, and feels perfect for tossing into a glove compartment, backpack, or suitcase. The phone weighs just 75 grams and measures 120 mm by 60 mm - about the size of a candy bar.

It easily pops open for swapping out the battery or adding a SIM card, which the user must provide, although it is designed to "borrow" the SIM from another phone during emergencies. The SpareOne comes with a single AA Energizer lithium battery, and the company says batteries from other makers may provide less talk and shelf time.

To compensate for its lack of screen and texting ability, the phone automatically responds with a message asking for a direct call when someone texts it.