This three foot long strand of DNA demonstrates the twisted ladder-like arrangement of DNA. The ease of twisting and untwisting this large molecule will help students visualize the 3-dimensional structure of DNA. The brightly colored base pairs and the dark contrasting deoxyribose sugars and phosphates in the rungs of the ladder make the model visible to all students during your demonstration. Carefully handmade using rugged flexible vinyl and hard wooden dowels. When completely coiled, the model is less than a foot in length for easy storage.