There are different types of towbars and you should make sure you know which one is suitable for your car and the purposes you are going to be using the tow bar for:
The two hole flange is the most common type of towbar in the uk, it can be used with a wide range of accessories such as bumper protection plates, cycle carriers and all types of stabilizers. Though they can sometimes pick up and interfere with reversing sensors.
The swan neck is the most common in europe, and is where the towball and towbar neck are all in one. They are suitable for an AL-Ko stabilizer though you are unable to use a cycle carrier whilst towing.
The detachable is becoming very popular in the UK, it appears the same as a swan neck towbar, but you can detach the neck by means of a simple action leaving very little or nothing of the towbar visible. They are very good if reversing sensors are fitted but as with the swan neck you are unable to use a cycle carrier whilst towing and other towball mounted accessories.