A VLS allows surface combatants to have a greater number of weapons ready for firing at any given time compared to older launching systems such as the Mark 13 single-arm and Mark 26 twin-arm launchers, which were fed from behind by a magazine below the main deck. In addition to greater firepower, VLS is much more damage tolerant and reliable than the previous systems, and has a lower radar cross-section (RCS). The U.S. Navy now relies exclusively on VLS for its guided missile destroyers and cruisers.