This is a short review of a very useful device which should greatly simplify the job of caring for and extending the lives of your LiPo (Lithium Polymer) batteries. There are two important points all operators of modern drones need to consider; periodic deep discharge and proper storage. Battery - Deep dischargeTo maintain their lives, it is recommended that LiPo batteries be cycled (deep discharged) every 20 cycles. Up to now, this has typically involved draining batteries by flying UAVs, usually in a low hover, until battery cells indicate a voltage of 3.3V. Having done so, batteries should then be full charged. This re-calibrates the batteries, thus enabling them to display a more reliable approximation of likely flight time. The downside of this method is that unnecessary wear and tear is caused to the UAV and its various components/moving parts.The Phantom Angel provides a way of deeply discharging DJI Phantom and Inspire batteries, that doesn't require the UAV to be flown. We have used these devices for the past year and have found them reliable and straightforward to use. We have just ordered a third unit for our Phantom 4 drone and will order a second Inspire 1 unit to help us maintain our growing collection of Inspire 1 batteries.Battery storageIn order to help prolong their lives, Lipo batteries should not be stored fully charged. In fact, most battery manufacturers recommend that the batteries be stored at approximately 50% charge if being stored for more than 24 hours.A very effective way to discharge to LiPos to 50% is to do so using the Phantom Angel range of products, which in storage mode, can drain a fully-charged Phantom or Inspire 1 battery to storage level in under half an hour.Note: Elevated Imaging Systems is not in any way affiliated or associated with this company, other than as happy customers, who have been impressed with both the products and supporting customer service. This is a product range that will appeal to both professional and hobby drone pilots and in our opinion, will help keep your batteries healthy and your drones safer. http://phantomangel.rocks