The TK1 series is an affordable alternative for providing comfort, protection and style. The TK1 features fully adjustable five position ratchet action temples with extendable length. Other features include a wrap around design and a one piece polycarbonate lens with integral side shields. The lightweight frame provides added comfort and balance. The polycarbonate lens filters out 99.9 percent of UV radiation that could be harmful to the eyes. Choose the best safety glasses, choose MCR Safety!