租车保险问题

Liability Insurance protects the driver against third-party claims for bodily injury or property damage as the result of an accident up to the value of the State Minimum coverage mandated by law, subject to the terms of the rental agreement. This protection applies to all authorised drivers of the rental car. Additional products may be offered locally to increase the coverage included above the State Minimum level.

这是在租车网上看到的有关第三方责任险的内容，没有明确说明第三方责任险的具体赔付数额，想问下这个到底是什么保险？是不是还需要再单独购买100百万的那个第三方责任险？