Check the listing for details. PROGRESSIVE KEYHOLE BRIDGE NO LINE BIFOCAL 3 Tier READING GLASSES SPRING HINGES. Color: Black, Clear, Tortoise, Condition: New with tags. Suitable for Reading. Listed at 17.99 USD. Normal 0 false false false EN-US X-NONE X-NONE INFINITE PROGRESSIVE BIFOCAL READING GLASSES New Arrival Incredible No line Progressive Bifocal Lenses give you a smooth, seamless progression. This High Tec Lens provides magnification for close work (choose your reader strength), then less magnification across the desk/computer distance and lower magnification for upper distance viewing. Example: +1.50=Up close bottom strength 150 progresses to zero power in distance. +2.00= Up close bottom strength 200, progresses to .50 power in distance. +2.50= Up close bottom strength 250, progresses to 1.00 power in distance.+3.00= Up close bottom strength 300, progresses to 1.50 power in distance. Size: diameter: 1-3/4"/height: 1-1/2"/outside width overall: 5-1/8" SPRING HINGESFREE SHIPPING TO THE USA FROM AN AMERICAN FAMILY OWNED COMPANY. WE SHIP DAILY M-F If you are happy, tell your friends! If not let us, know so we can make it right!