The Mutant Legacy features a magnetic lens change system, two different interchangeable colour lenses are included with each pair so you can quickly adapt to changing weather conditions. • The frames are made from TPU, a Thermoplastic polyurethane known for its, strength, durability and elasticity• Anti UV colours to eliminate fading and added Custom Venting Air Flow Technology (CVAFT) to give extra protection against dangerous lens fogging and giving you exceptionally clear field of vision• The Dirty Dog (CVAFT) ventilation system uses carefully chosen areas for the intake and exhaust of cooling air• The face foam is super soft open cell technical foam designed to maximise comfort• The Polyester elastic strap has an anti slip silicone bead on the inside• Produced with materials tested to -20 degrees so you can wear them with the confidence that they will perform as well as you will, sometimes better!• Extra large fit size