Are the lenses polarized?

No. The lenses are CR39 polymer with a rose-to-grey gradient and 100% UVA/UVB protection, but polarization is not listed.

What face size does the 53-19-145 fit suit?

That is a medium fit: 53mm lenses, a 19mm bridge and 145mm temples. It sits close to standard adult square frames, so very narrow or very wide faces should check the measurements against a pair that fits.

What is CR39 and is it good?

CR39 is a premium optical polymer that resists scratching better than basic acrylic lenses and is lighter than glass. It is a common choice in mid-to-upper eyewear.

What comes in the box?

The listing describes the sunglasses only. A case or cloth is not stated, so confirm with the seller if that matters to you.

How does Ember compare with a plain dark sunglass?

The gradient lens is lighter at the bottom, so it blocks overhead sun while keeping the ground and dashboard readable. A solid dark lens gives more overall shade in very bright conditions.