Towbay Type:

Fixed - Good old fashioned tow ball held on by two 16mm bolts, best type for caravans using stabilizers and for cycle racks, because the stabilizer plate or the rack bracket fits neatly between the tow bar face plate and the tow ball, with the electrical socket mounted along side the tow ball.

Swan Neck - Favoured mostly by continentals, very strong arrangement, but electrical plate usually mounted under bumper, very wet trouser knees! Both fixed and swan neck are highly visible, helps to keep other motorists away from your rear bumper.

Detachable - Expensive and invisible, so offers little protection from the enemy, keeps the rear end looking pretty.

Electrics:

Single - electrics or 12N (normal) socket usually for a trailer or boat trailer.

Double - electrics is where a 12N and a 12S (supplementary) are fitted, this system is sometimes used when towing a caravan, so that the refrigerator in the caravan is powered by 12 volts and the leisure battery is kept charged up.