This is a charging adapter for the Yocan B-Smart Twist Battery as well as other compatible batteries. This is a USB to 510 Thread External charging adapter.  

The Yocan B-Smart USB Charging Adapter is arguably the best option for Yocan B-Smart Battery users looking for a USB charger. It is compact and simple to use. The Yocan B-Smart USB Charging Adapter is equipped with all of the necessary features for connecting a 510-threaded battery to a USB charger. The Yocan B-Smart USB Charging Adapter was created to provide you with an efficient and effective way to recharge your 510-threaded batteries without the use of a traditional 510-threaded battery charger.

In The Box
1 Yocan USB to 510 Thread Charging Adapter