Suspected this could be rubbish, so initially only bought the one, but was that pleased promptly ordered another for my other bike. Convex mirrored surface is slightly bigger than new (2010) iPod Nano, fixes to bike via stretch rubber band that is long enough to wrap round front stem, normal sized top and bottom tubes, front fork or bar ends (if you've got them). Mirror has 360 degree rotation and good tilt range, both reassuringly stiff so getting the correct angle is easy and more importantly once adjusted, it says there. Vibration appears non-existent.
Mounted flush to frame, view is along top tube between your legs, so occasional tilting out of right leg helps get a fuller view but you soon get used to this so not a problem. Small and very discreet, but gives good warning of traffic coming up from behind, but (especially if frame mounted) obviously not a replacement for looking over your shoulder before moving out, but hey, even motorcyclists with full sized mirrors call this "the life saver".
Oh, and it's not 2kg as stated in the product description (a small fraction of that), but you never thought it was, did you?