Monstrum Ultra Series Scope Lens Covers help you keep your glass clean and damage free for when you need it most. Rubberized sleeves are crafted from an improved rubber formulation - designed to fit snug around your scope tube with more resiliency than ever before. Before purchase, carefully measure your scope for the correct fit. Measure the outside diameter of both the eyepiece and objective bell end of your scope. Select the lens cover whose range corresponds to the measured diameter. If diameter size is borderline, we recommend opting for the larger size. Each package includes one flip-up lens cover. If you want covers for both the eyepiece and objective of your scope, you will have to purchase one for each end.