The prescription lenses are ideal for those suffering from myopia (short-sightedness). They are made of tempered glass and built to be mounted exclusively on the dive mask models Big Eyes Evolution and Quantum. They are sold individually and are different for the left and right eye, so choose the right side and the correct diopter.Use extra caution for the assembly, we recommend that you contact a diving center or an optician.The lenses are made in Italy.