If you are a professor, teacher or student who is going to give a presentation, this 5mW violet purple blue laser pointer pen would definitely help you a lot. Human eyes are sensitive to purple blue color, so the violet blue laser light is sure to be more noticeable than other laser pointers. This pointer pen produces visible light beam in dark area and is great for pointing objects from long distance. And the laser beam can be adjusted by pressing the button. Power saving, compact and reliable, this 5mW 405nm Mid-open Laser Pointer Pen is of great use for life. With the high quality and great performance, we are sure this 5mW 405nm Mid-open Violet Purple Blue Laser Pointer Pen will be the best choice!