Prescription Bifocal Lenses$95.00 Per Pair (Near vision segment = 28 mm wide x 20 mm high) Prescription Bifocal Lenses quantity Add to cart Category: Uncategorized Related products #279 Smoke SpecThe #279 Smoke Spec insert fits most full-facepiece respirators. Click here for the Smoke Spec Insert Guide for examples of compatible masks. Click here for insert specs. Instruction Page. (does not include lenses) Add to cart test producttest $0.25 Add to cart