Scuba Choice Black UV Nearsighted Prescription Corrective Optical RX Lenses Swimming Goggles UV Lenses- "Size" means Size means lens prescription. 2 spare nose bridges included. Please round it to the nearest (lower) number of your prescription. for i.e. if your prescription # is -3.25, you should select -3.0. Never select higher then your prescription number, as it might cause extra strain for your eyes.