Suppose I have a set of multipartite orthogonal product bases, which I want to prove as possessing some quantum non locality. i.e they can't be distinguished perfectly with local operations and classical communications. So one way which I found is to show if they are unextendible product base sets, because that implies that states are nonlocal for measurements. But, is the negation also valid? If the set isn't unextendible product bases, then does it imply that the states don't show any quantum non locality?