So there is a promotion about this new mobile battery, it's kinda unique for some people especially have USB-C laptop and Nintendo switch.
1. It support USB PD protocol, which means it it cover 9V/2A, 15V/2A, 20V/1.5A
for Macbook as well as iPad Pro and Nintendo Switch fast charging.
2. It also provide a unique Hub features acts like a USB data hub
when charging your laptop.(see feature description from the link) a good usage is charging both your phone and laptop the same time sync data with your phone.
There is a clickable promotion under the price, and here are the two promotions:
1. Receive 1 $9.99 [3-Pack] USB to Type C 3.0 Adapter free when you purchase 1 or more All Qualified Type C Power Bank offered by Sunvalleytek. Here's how (restrictions apply)
2. Pay $59.99 for the RAVPower 20100mAh Hubs PD USB-C / Type-C Port Portable Charger offered by Sunvalleytek.
So the final price will be $59.99 for the battery plus USB to Type C 3.0 Adapter bundle.
Then there is a YMMV part:
after you added the bundle to your cart, it only has $10 promotion applied, so I chat with Amazon service after placed the order. The kindly refund me $10 for the missing promotion credits.