Cyclops Depth Module MK1

The Reinforcement Module upgrade is an upgrade that increases the dive depth of the Cyclops (this feature has not been implemented though stated by the tooltip). It can be added by placing the module inside a Cyclops's upgrade console located in the engine room.

Currently, the Carapace Reinforcement Module and Reinforcement Module both require a Reinforcement Module in their recipe. While the Carapace upgrade may still require it in the future, it is unusual and possibly a bug for the Reinforcement Module's recipe to require itself.

Speculation
A screenshot by the developers seems to imply that adding this upgrade to the Cyclops will increase its crush depth from 200 to 1200 meters and its safe depth from 100 to 450 meters. However, in a Trello entry by the developers, an increase of the crush depth by 100 meters per Reinforcement Module upgrade installed. It may also be just a temporary upgrade that might get removed in later builds.