View the Moon or Venus with less glare. Screw this onto the bottom of your eyepiece or star diagonal and enjoy more contrast.
Two polarizing filters are mounted on a swivel, allowing the user to vary the filter's transmission from 3% to 40%.
The filter can also be unscrewed at the swivel. Screw one half into an 1.25" star diagonal, the other half into the eyepiece, and simply rotate the eyepiece to vary the brightness.