When%20you%20are%20lining%20up%20a%20shot%2C%20clean%20functional%20optics%20are%20an%20absolute%20necessity!%20Protect%20your%20optics%20from%20dust%20and%20abrasion%20with%20the%20Monstrum%20Tactical%20Flip-Up%20Rifle%20Scope%20Lens%20Covers.%20The%20spring-loaded%20flip-up%20mechanism%20pops%20open%20effortlessly%20when%20needed%20and%20clicks%20shut%20when%20closed.%20Made%20of%20durable%20rubber%20and%20polymer%20materials%2C%20they%20wont%20damage%20the%20finish%20of%20your%20rifle%20scope%20while%20shielding%20the%20lenses%20from%20the%20harsh%20elements.%20The%20Flip-up%20Lens%20Cover%20attaches%20with%20a%20flexible%20rubber%20collar%20that%20allows%20each%20size%20to%20fit%20securely%20along%20a%20range%20of%20diameters.%20It%20also%20prevents%20the%20lens%20cover%20from%20moving%20or%20rotating%20during%20shooting.%0AEach%20package%20includes%20one%20Flip-Up%20Lens%20Cover.%20For%20optimum%20fit%2C%20carefully%20measure%20the%20diameter%20of%20both%20your%20rifle%20scope%26rsquo%3Bs%20eyepiece%20diameter%20and%20objective%20lens%20diameter%20and%20choose%20the%20size%20from%20the%20chart%20below.%20Example%3A%20if%20your%20eyepiece%20measures%2031mm%2C%20then%20you%20should%20order%20Size%20C%20so%20it%20fits%20tighter.