This high-quality accurate neutral-density filter transmits only 20% light. This reduces glare and brightness to allow the user to relax the eye seeing more detail of our brightest celestial neighbor. It will also and most noticeably reduce the loss of night vision.
This unit has a precision machined anodized aluminum cell. (Some moon filters are made using a plastic cell that can quickly become damaged in use.)
With it's standard 1.25-inch filter thread (M28.5x0.6), it can screw into any 1.25-inch eyepiece. It is protected in a plastic case.