Each 7-stack of laminated tear-offs has a strip of clear adhesive around bottom tear-off. To install, it sticks to the lens. Creating a ‘seal' around the perimeter, between the lens and tear-offs. Preventing moisture or debris from getting between the tear-off stack and lens. Because if water gets between there (common battle in the goggle world) the tear-offs become irrelevant - you’re still seeing the water or debris since it is below the bottom tear-off. Definitely for the very serious racer, not the average rider.