Amazon also shows this note about the mirrors:
NOTE : Because of the small dimensions of the mirror glass, this product must only be fitted for racing or show purposes.
This happens to be a valid comment by Amazon because of the size requirements for mirrors in the USA.
For example - in Pennsylvania:
http://www.pacode.com/secure/data/067/c ... 5.148.html
§ 175.148. Mirrors.
(a) Condition of mirrors. Mirrors shall be in safe operating condition as described in § 175.160 (relating to inspection procedure).
(b) Rearview mirrors. A motorcycle shall be equipped with at least one rearview mirror or similar device. If a certificate of exemption for a sun screening device or other material has been issued, rearview mirrors, each with a minimum reflective surface of 12 1/2 square inches for a flat mirror or 10 square inches for a convex mirror, shall be installed on both sides of a motorcycle. A vehicle for which a certificate of exemption has been issued for medical reasons may be equipped with only a left outside rearview mirror, unless originally equipped with an outside rearview mirror on both sides of the vehicle.
(1) A mirror may not be cracked, broken or discolored.
(2) A mirror shall hold adjustment.
(3) A mirror shall provide an unobstructed view of the highway to the rear of the vehicle for a distance of not less than 200 feet.
(4) A mirror shall provide a minimum reflective surface of 12 1/2 square inches for a flat mirror or 10 square inches for a convex mirror.
I don't own Magazi mirrors, and have no idea if they are legal size. Regardless, there is probably little chance of getting stopped by a cop with a tape measure.
As I said - Up to you