The Cobblestone Drive is an upgrade to your Exo-Suit. On occasion, the Cobblestone Drive will produce 1 cobblestone, which will be placed in your inventory, or if your inventory is full, drop one block of cobblestone on the ground. This can be useful if you're crossing a large gap (I.E. A ravine) and need a building material to cross (I.E. You only have gravel, which falls). Remember to activate the upgrade in your Exo-Modder.