Criteria for selection is minimum flow, normal flow, maximum flow and pressure drop across the valve. 选型标准是最小流量，正常流量，最大流量和通过阀门的压降。
Pages are reformatted and compressed before being sent to the phone, so they only use about one fifth of their normal amount of traffic. 发送之前，对面进行重定格式和压缩，所以流量仅是正常流量的五分之一。
