Exterior rear view mirrors are part and parcel of every new car. There is not a new car in the car park that doesn't have a driver and passenger side external mirror. While these are important for day to day driving, especially when changing lanes, they take on a new meaning when towing. When towing, it is important to see down the sides of your trailer so you can make sure you stick to your lane and come in handy when going down narrow streets with parked cars. When reversing is where they come into their own.
Towing Mirrors Temporary
The width of your trailer will let you know if you need towing mirrors to extend your view so you can see around your trailer. These come in a variety of different shapes and styles including how they are mounted. Some simply clip onto your existing mirrors to make them longer and stick out further. Ones that go onto larger vehicles have struts and braces to hold them on. They can use magnetic mounts or straps as anchor points and are a temporary arrangement only used when towing a trailer.
Towing Mirrors Permanent
There are permanent towing mirror solutions that have flexible brackets that can move in and out. The mounts to the body of the door are permanent. (screwed or bolted on) The flexible mounts are then loosened, the mirror is then adjusted to suit the best view and then the mounts are retightened. These look ok on a crew cab truck, not so good on a car.
Blind Spot Mirrors
Blind spot mirrors simply stick onto your existing external rear view mirror and offer a larger field of view. This is so you can see if a car is in your blind spot. The mirrors have a self adhesive backing so are easy to put on. A lot of new vehicles have blind spot detection which lights up a coloured spot on the mirror if a vehicle is in the blind spot.