Some CB radios have a PA out feature that allows you to connect a PA speaker to communicate with people outside your vehicle. This is one-way communication (they can't answer you through your radio), but it can be helpful in some situations. We have a variety of PA speakers for your CB in different shapes and sizes. The 5 inch speakers are the size most commonly used for CB. It is important to note that unless a speaker's description specifically states that the wire and plug are included with the speaker, they probably aren't. For these we carry a PA speaker wire.