I had no problems with the guides. Clear, high-quality slides that fit easily in the microscope. Good selection of specimens, slides made in Japan. My 8 year old really liked these slides and was more interested in biology which was the reason for the purchase. Everything is plastic so don't worry about younger users breaking the slides. The only complaint I have concerns the boxes. The boxes are made of thin cardboard and are cumbersome to handle or practical. I would like a plastic case with a lid to hold slides and store them.