Molecular Model SetsHands-on exploration of organic and inorganic compounds. High quality molecular model kits that will last a lifetime. These detailed kits allow you to build simple inorganic compounds such as H20, NaCI, H2SO4, O2, and C12; simple organic molecules such as ethylene, acetylene, and propane; or complex compounds such as sugar and cyclohexane. Made from a super strong, unbreakable pre-colored plastic. The connecting bonding plugs fit securely yet are flexible enough for double bonding applications. The balls are precision drilled for correct bond angles.