The Yocan B-Smart Battery featured Customize Voltage Option(2.0V to 4.2V), allows you to find your sweet spot with precision.
And it comes in various subtle and lively colors like black, silver, blue, red, and gold.

B-Smart Features:
320mAh Battery Capacity
Preheat Mode: Click the power button 2 times
1-Ohm Resistance
10-Second Pre-Heat Function

More detail: Yocan B-Smart Battery

The price is 10.99USD for one piece.