Microphones.

New CBs always come with a standard type of microphone, but there are other microphones available.
Many different types of microphone have been made for CB and they range from replacement basic microphones to expensive base station microphones. Some types are made for certain use, such as base or mobile, but many are designed to improve your sound in some way.

Although non-standard microphones are supposed to improve your outgoing sound, care must be taken in choice of microphone and the settings used on that microphone.
It must be noted that, with FM CB, boosting your outgoing sound too much can easily start interfering with other channels and CBers. The spacing between CB channels allows little room for sound. The best improvements are usually made by careful shaping of the outgoing sound, rather than just boosting it.