NIGHTFORCE NXS 15x-22x Eyepiece Flip-Up Lens Cap A473 > The new lens caps provide both superb protection and extreme functionality in the field. For the scope's objective lens, an adapter screws into the objective's threads; for the eyepiece, the adapter clamps on. The caps themselves then securely lock into place onto the adapters. Both caps flip up with finger pressure. Once open, the caps can be locked into place with slight backwards pressure. The caps can be rotated to provide the opening angle preferred by the shooter. Nightforce lens caps are made of extremely tough, heavy-duty black plastic. Unlike lesser quality covers, they will not accidentally detach from the scope, they are not affected by extreme environments, and they will not deteriorate. They are designed specifically for high-quality scopes, providing years of effective protection against dust, moisture, abrasion and scratches. They are quick in the field with positive response, designed to be left on the scope at all times.