Legal CB.

Even if a product is not specifically illegal, using any item in a way that makes the system operate outside of the specified legal limits may render a person liable to prosecution.
The following are examples, other products may also cause such issues. As a general rule of thumb, be aware of any accessory or add-on circuit which offers you improved performance from your present equipment.
Amplified microphones: If turned up to high, deviation is likely to exceed legal limit. Also likely to cause interference, which may be reported.
Speech processor: If turned up to high, deviation is likely to exceed legal limit. Also likely to cause interference, which may be reported.
Other examples exist and, as a general rule of thumb, be aware of any accessory or add-on circuit which offers you improved performance from your present equipment.