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: Adjustable Iris M30toM37*2 Aperture: 1.5-26mm Adjustable To Fit Lens Front: 30 mm, 36 mm Type: Lens Reversing Adapters All metal aviation materials Compatible with PVS-14