I didn't realize there were four in this packaging. Very good value for money. However, it doesn't work with my Mophie battery box. That's probably simply because the Mophie case isn't designed to be discharged. I have a MVP5 vape mod/battery with USB-C charging and it sounds really slow. Again probably the same problem as with the phone case. I probably want it to spin a bit slower so it uses less power. In general, the purchase is satisfied.