This sale is for 25 optical inserts.
Avon M50 C50 Series Gas Mask Optical Insert for vision correction.  Contact your optimetrist for lenses you just pop in.  These are brand new in package.  Shipping is free in the US.
This is a must have for any owner of an M50 or C50 protective mask who wears glasses.  This is the only way to wear your prescription eyewear while maintaining a proper seal on your mask.
There are two versions of the inserts.  They hold the same lenses and the black frames are identical.  The only difference is the way the lens holder connects to the black frames.  Your order may contain either version.