A PADD, showing its isolinear chip.
The Starfleet-issued isolinear optical chip is a small, flat, rectangular unit featuring on board nanotech processors to aid in memory access and with a maximum capacity of 2.15 kiloquads. Though normally easily corrupted, chips may be coated with a layer of clear plastic for protection in environments more hostile than a computer core without affecting read and write capabilities; such ruggedized chips are commonly used in tricorders, PADDs, and other handheld devices with isolinear chip drives.
Without the protective coating the user must wear special gloves to remove the isolinear chip.(Star Trek: The Next Generation Technical Manual)