Using knob button ?? press it to switch brightness and color temperature .when rotating it ?? the brightness (20%-100)?? or color temperature (3300K-5600K) parameters will be increased or decreased .</br>Topest CRI95 cab completely with perfect color of sunlight and ensure that its light is natural lifelike .apply to portrait ?? children is ?? wedding and new photography etc.</br>Has two kinds of power supply mode ?? you can use Lithium battery such as NP-F550/F750/F960 series when outdoor ??and use the AC adapter when indoor . Please NOTE : the LED light doesn't include battery and AC adapter ?? if you need ?? please contact me before you order it