Related to the Polarization subject, when you are shopping for Polarized sunglasses, then take two copies of the sunglasses and placed them so that you are look

Related to the Polarization subject, when you are shopping for Polarized sunglasses, then take two copies of the sunglasses and placed them so that you are looking through both lenses, but one in 90 degree and notice if it turns opaque-black. Many times in the past when I was looking for some cheap polarized sunglasses, I found that some were actually falsely labeled.