I bought it to charge Ring Doorbell 2nd generation. The Ring isn't really an acceptable solar doorbell charger, and I didn't want to spend $50 on a Ring solar panel that I'd have to customize anyway. So this one seemed reasonable at $21. A few tweaks to the cord and doorbell bracket keep my doorbell charged - I no longer have to take it off the wall to charge every 6 weeks. The battery is currently at 91% charge.