Which of the following Firebox devices features external antennas?

The Firebox device that features external antennas is indeed the XTM 25-W. This model is specifically designed to support external antennas, which provide flexibility in deployment and the ability to optimize wireless coverage in various environments. External antennas can enhance reception quality and extend the range of the wireless network, making them beneficial in scenarios where users require a robust wireless signal.

In contrast, other models mentioned do not have this specific feature. For instance, the XTM 30, XTM 33-W, and XTM 22 are configured differently and may either include internal antennas or have different specifications that do not involve the use of external antennas for wireless connectivity.