or those of you looking for a little extra strength reading when looking at your Computer or Gauge, Sherwood has the mask for you. Sherwood took one it's best selling and best fitting masks, the Sherwood Oracle, and made it even better. Now with +1.75 Positive Diopters located at the base of each lens, the Sherwood Oracle+ delivers that added dimension. Think of it as bifocal glasses built right into the mask.