What is the difference between the manifolds $ S^{1} {×} ̃ S^{2} $ (skew product) and $S^{1}×S^{2}$?

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What is the difference between the manifolds $ S^{1} {×} ̃ S^{2} $ (skew product) and $S^{1}×S^{2}$ ?

Thank you in advance.