Leupold Pro Gear Alumina 50mm 2.50in Long Screw On Shade Mount Aluminum Matte Lens Black. The cover opens silently and folds flat against the scope in the open position. Constructed out of durable 6061-T6 aircraft grade aluminum they are precisely machined to allow for quick and easy operation and a low-profile position when open make these Flip-Back lens covers stand above the rest. Round objective and ocular models can be rotated so they can open in any direction. Specifications for Leupold Pro Gear Alumina 50mm 2.50in Long Screw On Shade Mount: Manufacturer: Leupold Fabric/Material: Aluminum Attachment Type: Screw Package Contents: Leupold Pro Gear Alumina 50mm 2.50in Long Screw On Shade Mount Leupold 182904: Pro Gear Alumina 50mm 2.50in Long Screw On Shade Mount Aluminum Matte Lens Black