This extraordinary Panerai depth gauge represents a fundamental piece of technical equipment supplied to the Italian Navy Commandos (Comsubin). The piece presented here is equipped with a 40-meter graduated scale, this specific configuration, along with the 30 and 50-meter versions, identified the versions defined as "Defense", which were primarily used in delicate mine clearance, training, or recovery missions.

The defining feature of this instrument is its self-illuminating dial, thanks to "Luminor", the tritium-based luminescent substance patented by Panerai, the depth gauge guaranteed perfect visibility even in absolute darkness. During night operations or in low-visibility waters, it allowed the operator to constantly monitor their diving depth.