These are GENUINE Miltex Oculus Loupe Spectacles.  The Loupes themselves are removable, and can be placed on other frames.  These frames accept prescription lenses!  Frames are 140 size.

Milliex sells a kit to change/upgrade the lenses to 2.5x. Price of that kit is $161 from Milltex.

These are configured fixed 1.8x as we have them in stock and ship to you.