NOTE: Quantity is per tube. You must select quantity of 2 for DUAL TUBE Systems. The package includes only the focusing aperture, not the night vision device. Please verify the quantity before completing your order. FEATURES: The focusing aperture is an advanced Night Vision Goggle (NVG) accessory designed to enhance visual clarity at various distances. It features a smooth-action, high-performance optical iris that adjusts quickly to ambient light conditions by opening or closing as needed. The device includes a replaceable Corning Glass sacrificial lens for added protection, which can be changed without tools. This lens helps shield the NVG from dust, debris, and scratches. The focusing aperture allows users to maintain clear vision at all distances without refocusing the NVG. The iris adjustment provides variable light control to optimize performance in changing light environments. Adjustment is made by turning the control ring to open or close the iris as required. The unit attaches securely and easily to the front of compatible NVG models. Compatible models: TYPE 1 VARIANT (NAVAIR) 37mm OD: AN/PVS-6, AN/PVS-7, AN/PVS-7B/D, ANVIS-9, AN/PVS-14, NEPVS-14, AN/PVS-23 (F5050YG), DTNVG, DTNVS, RNVG, TNVC-BNVG-M (Artemis), MOD3 TYPE 2 VARIANT (GROUND) 34mm OD: AN/PVS-15, AN/PVS-18, AN/PVS-31A, BNVD, MUM-14, GPNVG