Just as already for conventional lead–acid batteries with liquid electrolyte, where optimum battery designs for the various applications have evolved with optimized separators, so also for VRLA batteries different requirement profiles demand special separator characteristics. The recent developments have shown strengths, but also weaknesses for the existing separation systems and thus have given impetus to intensive further development. Probably none of the alternatives presented here will displace any other completely; on the contrary, they will be forced to compete in ever optimized versions for the various applications. It certainly will remain interesting!