Siraya's feather-light Alpha professional sports sunglasses wrap and hold the temple, establishing maximum vision from every angle. The adjustable rubber nose piece prevents slippage, and provides the support needed for riding in almost any weather conditions. Siraya's Alpha professional sports sunglasses are made of TR-90, a Swiss developed thermoplastic material that is extremely durable, flexible and lightweight. This flexibility makes the Alpha frames extremely comfortable, even under the pressure of fast movement. They're also resilient to damage when met with high impact collisions. All of Siraya's pro sports sunglasses feature ZEISS lenses made in Italy. This pair of sunglasses feature ZEISS brown P8010 Tri-FlectionTM Lenses, which are ideal for environments with a high prevalence of the greens and browns that you might typically encounter when mountain biking or hiking.