Kit Contents:
20 black 4-peg carbon atom centers
13 white 1-peg hydrogen atom centers
6 white 2-peg hydrogen atom centers
7 black 3-peg carbon atom centers
16 blue 4-peg nitrogen atom centers
5 red 4-peg oxygen atom centers
45-1.25" PVC, clear bonds (single bonds)
30-1.625" PVC, clear bonds (double bonds)
7-2" PVC, white bonds (H bonds)
5-.75" PVC, white bonds (glycosidic bonds)

Build and H bond adenine to thymine, and guanine to cytosine. Other N bases (uracil, caffeine, theophylline, and theobromine) can also be made with the kit.