These prisms by #Glydein are a great way for teaching my kids all about light and light refraction and how light can pass through certain things and not others. Also a great tool for photography. These prisms are stellar and of top quality and are definitely worth the price of $23.99. I'm only a parent and grandparent but this would definitely make a great gift to any 4th or 5th grade teacher, a science teacher as a way of saying thank you or for yourself if a parent or grandparent to teach hands on the importance of light and light refraction.