Due to its strong straight light, laser pens (pointers) are widely used in teaching, astronomy etc. Just push the button, then you will see striking light shoot. It is alright to point at any targets such as photos, PowerPoint, monitor etc. It may be the proferred choic for astronomy fans, laser fans. Friendly Reminder: 1. The laser is high power. So it runs out of battery quickly. And please do not keep the laser on continuously for more than 20 seconds or it will get burnt from inside easily.2. The use of the laser beam is absolutely does not allow the irradiation of the eye in front of humans and animals!3. Remove the batteries when not in use.4. Batteries are not included.