Adjustable iris aperture：sizes m30 to m37,apertures1.5-26mm iris,min Diameter1.5mm, Max Diameter26mm Reliable Materials:Aviation metal,Rugged and very reliable performance Simple Operation: Just use the handle to change the aperture diaphragm diameter, which is easy to operate and more directly for adjustment. Type: Lens Reversing Adapters,adjustable iris diaphragm for PVS 14 night vision deviceand other equipment Product details: dimming aperture + 37mm UV lens Mount: M30 to M37 To Fit Lens Front: 30 mm, 36 mm Aperture: 1.5-26mm Adjustable Min Diameter: 1.5mm, Max Diameter: 26mm Ｍaterial quality：Aviation metal For PVS14 night vision monoculars and night vision binoculars