Real x-rays printed on durable, long lasting plasticnCan be used on overheads, windows and light tablesnFeatures 13 species and an activity guide to learn about the skeletal systemnIdeal for grades K through 4nRoylco animal X-Ray set includes 13 real x-rays measuring up to 8 x 10 inches and an idea guide. X-rays are printed on clear, heavy duty plastic making them ideal for use on light tables.