It also depends on where you are located, since CB is different in some countries. If you are in the US, where we’re based, there are a couple of other options besides the PRO401HH that may work for you.
The Cobra HHRT50 Roadtrip is a portable handheld CB radio that can also be used in a vehicle. It comes complete with an external magnet mount vehicle antenna and a removable antenna on the radio itself, so you can easily swap it out for use either inside or outside the vehicle.
Another option, which may be even more appealing for your application, is the Midland 75-822. This is a 2-in-1 CB radio that is literally plug-n-play. It’s one radio with a detachable battery pack that can be swapped out for a vehicle power adapter, turning it into a hand speaker mic radio when in your vehicle. This is pretty cool for any radio, but it is perfectly fit for CB.