Tilos Universal Mask is a truly versatile mask that fits most faces. Prescription is also available in a wide range of diopters, including gauge reader magnifiers. Please message us at email@example.com if you choose to purchase your mask with prescription or bifocal lens with your preferred diopter strength. Full lens prescription available in Diopters -8.0 to +3.0. Gauge Reader Magnifiers available in +1.75, +2.25 and +2.75.