Available in multiple strengths:+1.0 / +1.5 / +2.0 / +2.5 / +3.0 / +3.5 / +4.0 — choose the perfect magnification for your needs. Magnification Strengths: +1.0 to +4.0. ????Spring Hinge Flex Design. Flexible spring hinges provide a comfortable fit for all face shapes without pressure.