I have used this clip on mirror system; they are adequate but tend to vibrate blurring the view:
http://www.etrailer.com/pc-M~7070.htm
I now use this slip on mirror; much improved with very little vibration. Read disclaimer as this style does not fit all models.
http://www.etrailer.com/p-CTM2200A.h...cleid=19996978
Dick