THIS IS A DROP SHIPPED OR SPECIAL ORDER ITEM. PLEASE CONTACT OR LEAVE A NOTE IN THE COMMENTS BOX REQUESTING ESTIMATED WAIT TIME FOR SHIPPING. An HVO Drone is used to add compression capacity when the number of oxycons exceeds the capacity of the Master compressor. A Drone includes a tank and a compressor that responds to a signal from the Master to turn on and off. The Master and Drone tanks are connected via a braided steel oxygen line (included) to create a single "atmosphere" that has a common pressure. This pressure is sensed by the Master to maintain the pressure in all tanks within the range that is appropriate for your system (30 - 100 PSI for the Standard, 100 - 150 PSI for the MAX and Mighty Mite). When adding a Drone, pair a Standard Master with a Standard Drone. Mighty Mite and MAX products may be combined. Here’s a quick video on how to setup a HVO system.