Abstract: Apparatuses and methods for compressed fluid vessel monitoring can permit a user to more easily order replacement vessels, monitor use, monitor inventory and return empty vessels. Embodiments can utilize a collar connectable to a vessel to help facilitate such functionality. The collar can be adapted to transmit signals to a data processing system. The data processing system can be adapted to permit a user to track the location and fill status of the vessel as well as order a replacement vessel and disposal or return of an empty vessel. Instrumented vessels can also convey sensor data to help identify a leak condition or other condition of the vessel. In some embodiments, the data processing system can be adapted for integration into a user's inventory system and/or purchasing system as well as a supplier's system to facilitate communications concerning vessel fill status, reorder, and/or vessel return.