Flip-up sunglasses are convenient for casual wear when moving back and forth between indoors and outside. With just a lift of the front lens, the shades become clear and allow the wearer to see in lower lighting. When it's time to head outside, the tinted lenses flip down to protect the eyes from harmful UV rays. The frame is made of thick, durable plastic, while the round lenses are a strong metal. These sunglasses come in silver, gold, orange, yellow, blue and purple variations.