Please let me state you can get these FMC Button lenses from www. Cockpitsimparts much cheaper than the ones here! This is a limited run for those wanting a higher FMC finish. These are very difficult and time-consuming to make. 
 
These do not fit the new v4 PCB version!
 
These have been created at the request of several people that wanted to improve their 737 FMC builds. I have developed these new, improved designs over the last year. What makes these button lenses different from cockpitsimparts ones is that I have purposely slanted the laser head by 2 degrees to create wedge-shaped lenses. These lenses are also painted on five of the six sides. This results in no light bleed around the button edges, and the more the lens is pushed into the button cap, the tighter the fit, creating an almost perfect join which is hard to see. This makes the button cap and lens look like it's one part.