Round Acetate Sunglasses Tortoise Pattern. Amber Lens. The Alder Sunglasses are a Sophisticated addition to the OTC family. The frames are the best quality hand-wrought Cellulose Acetate with a Polished Gloss Tortoise Pattern. The lenses are a light weight polarized amber that are rated UV 400 and scratch resistant. The Alders are a great go to style when not going out with side-shields.