Only three countries on Earth require either planar (flat) mirrors or the moronic phrase that should say instead "this mirror is useful".

Combining the slight convex overall curve that is spherical with the outer edge being also likely spherical just a smaller radius gives you in-effect a bubble mirror with no frame that perfectly blends Into the main reflection.

As you overtake a car in the next lane you will see it "stretch" into view. The line in the mirror makes a perfect reference for safe passing. When the line in the mirror is in the center of the car in the next lane you have 2-3 car lengths between your cars it's a very comfortable buffer.

When the near headlamp makes it past the line I think you have a couple meters so you could fit in a tight spot. I've been meaning to measure but haven't had a chance yet.

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2011 E70 • N55 (me)
2012 E70 • N63 (wife)