Polarized Riflescope Filter for the Brown 97D Riflescope also fits the Mueller APV riflescopes. This polarized lens screws onto the objective lens of your riflescope and reduces the effects of glare, haze, reflections, and mirage. A target shooter can see sharper contrast and a clearer sight picture. A prairie dog shooter can aim with less mirage. A sniper can see more of what's hidden behind window reflections. The effect is very much like wearing polarized sunglasses... Everything gets clearer. Not a Toy Plastic Lens Cover! This is optical camera glass, clear and distortion free. Screwed onto your objective lens, it Polarizes your image BEFORE it enters your scope. That way only the polarized light gets enhanced by your scope. (no sense magnifying the bad light). The polarized lens actually turns in it's mounting and you dial out the bad light no matter what the angle of light or time of day. The effect can be dramatic... We don't recommend our polarized riflescope filters for low light shooting. But if you shoot with a riflescope during daylight, especially when the effects of glare, haze, reflec-tion, and mirage are present, a polarized riflescope filter is highly recommended. See all of our scopes, filters, and accessories at our Riflescopes Home Page.