Many people in the US retire to their motor home for a life of travel on the road. However, you will not get far or travel safely without some blind spot mirrors.
Your motor home will come with side mirrors attached. These will give you a view down the side of the vehicle. Which view you get depends on how you adjust them, but people often angle them so that the driver can see part of the side of the home in the mirror. This is so they know what they are looking at in comparison to their vehicle.
However, that set-up will still leave a large area behind the motor home which is invisible and areas down each side where nothing can be seen. The side blind spots increase further back you look. It is very easy for another vehicle to be sitting behind or in the rear quarter area and be unseen by the driver.
Blind spot mirrors are an attempt to combat this problem by giving a wider or alternative view. The extra mirrors will be angled differently so that they cover a different field. By looking at both mirrors, the driver will be opening up some of the blind spot area.
The mirrors come in various designs. They might attach directly on to the side mirrors just to give a new angle. They might be bubble mirrors, looking at the same place but with a wider perspective. They might be on brackets which hold them much further out from the side. This will give a much wider angle and allow some vision of the area directly behind the vehicle. Convex mirrors on the near side can offer a wider view of the area furthest from the driver.
Blind spot mirrors do not cover all the blind spot, but they are a start.