[Elecraft] Optivisor?

[Jerry Flanders]

At 09:49 PM 6/26/2008, TMorton wrote:
>Looking to buy an Optivisor over the internet but not sure what 
>power to get...I usually wear 1.50 or 1.75 cheaters  to read...any 
>suggestions for what to get to be able to solder those itty, bitty 
>Elecraft parts?

FYI - usually the number represents Diopters, which is the unit used 
to express the power of a lens. It is the reciprocal of the focal 
length expressed in meters.

A lens with a diopter of 10 would enable your eyes to easily focus at 
1/10 meter (3.9 inches). One with 5 would work well at 1/5 meter (7.8 
inches), etc.

Jerry W4UK