He said that his father is a college teacher. He uses this special pen when he has classes. He can use it to control the PPT. It is very useful and convenient. And also this a birthday present sent by his students. Furthermore, his student bought this item on an online store. There are many kinds of the items. http://www.dinodirect.com/laser-pointers/. On the next birthday of my cousin, I send him a laser pointer. It is really very useful and helpful. Hope I can also help you. Thank you!