For the darkest lenses, there are a few options Ray-Ban has to give you the least light transmission:
DARK GRAY LENS - Boosts contrast and transitions well over a wide variety of conditions. Dark Gray lenses filter blue light to enhance visual acuity and improve depth perception. Excellent for mountain biking and golf, and any other sport that takes you in and out of shaded areas.
GREEN LENS - By absorbing 85% of visible light and blocking out most of blue light, the green lens ensures the darkest coverage, better clarity of vision and remarkable color contrast, especially best for hot, sunny conditions. Photo Source: Frame Geek
Ray-Ban primarily makes their sunglasses using 2 materials for lenses, Crystal and Plastic. Keeping this in mind when deciding on dark coverage, select a Green or Dark Gray lens made of the either of the following materials:
PLASTIC - The plastic Ray-Ban lens is best in transitioning from dark to light thanks to a precise chemical immersion process.
CRYSTAL - The crystal lens is tinted on the backside using high vacuum processes. This allows for intense color contract and smooth color transitions.