On the Yocan stix vape pen body, you will get a power button used to turn on and control temperatures of the mod according to your vaping style. It is fitted with a LED indicator that outlines the firing button, which lets you know the charged amount left in your device.

What do the colors mean on Stix?
The color Red represents the lowest heat settings while the green LED light signifies the medium heat setting and the blue colored LED light means that you're already running the highest temperature level.