Damaged or missing parts can only replace with original Walterscheid parts and retrofit them in accordance with regulations and after consultation with Walterscheid.

Most binoculars are either roof or porro prism designs, but there is also a third option: Reverse Porro Prism.

Phase-coatings are often applied to binoculars with a roof prism (as opposed to Porro prisms) to help keep the light from going "out of phase" as it passes through the prism.

Roof prism models look like two straight monoculars connected together in the middle, while the eyepieces are closer together than the main optics of Porro prism binoculars, angling the light path. Avid amateur astronomers themselves, they've tested products in the field and can provide personalized recommendations. There are pluses and minuses to both, although CF, or Center Focus binoculars are much more popular. Most binoculars that are water resistant can get a little wet as long as you dry them off as soon as possible, but they will not keep liquid out if submerged or kept wet.However, the movement of the eyepieces was so large and the collimation was so bad that I quickly gave up using the binoculars. Minimum Inter-pupillary distance, therefore, is the measurement in mm from the center of the left eyepiece to the center of the right eyepiece when the binoculars are "folded in" as far as possible.