Double Helix Model

I wish I had read reviews prior to purchasing this item; since everything else was so expensive, I elected to just buy it rather than researching. I purchased this item to teach early elementary children about the basics of DNA. I was hoping that the children could put this model together as one of the class activities. The item arrived in a torn bag, with no instructions on assembly. The quality is very, very poor, consisting of flimsy Styrofoam pieces that need to be inserted into two curled plastic strips. What I thought would be a central rod to stabilize the structure was actually a series of small plastic pieces that snap, with great difficulty, onto one another. Overall I think it add something to the class but very disappointing.