Which of the following devices requires a number share?

The device that requires a number share is the Palm device. The Palm is designed to operate as a secondary device that uses a feature known as number share, allowing it to share the primary phone number associated with a main mobile device. This functionality is particularly useful for users who want to have a secondary device, like the Palm, that can make and receive calls and texts using the same phone number without needing a separate line.

In contrast, devices like Hum Essentials and ARLO GO do not require number sharing since they serve different types of functions. Hum Essentials is primarily a vehicle connectivity service that provides safety and diagnostic features, while ARLO GO is a mobile security camera that relies on its own cellular connection for data, rather than sharing a phone number. Therefore, the Palm's unique requirement for number share sets it apart as the correct answer.