Adjustable iris aperture：sizes m30 to m37,apertures1.5-26mm iris,min Diameter1.5mm, Max Diameter26mm Type: Lens Reversing Adapters,adjustable iris diaphragm for PVS 14 night vision other equipment Easy to use: Just use the handle to change the aperture diaphragm diameter, which is easy to operate and more directly for adjustment. Reliable Materials:Aviation metal,Rugged and very reliable performance Product details: Adjustable iris Ｍ30-M37 * 2 + 37mm UV Filter * 2 + 37mm Lens Protective Cover * 2, Can be used in combination. Adjustable Iris Aperture Diaphragm 1.5-26mm Iris Aperture Diaphragm Adapter M30 to M37 Diaphragm Lens Module Adapter Ring Compatible PVS-14 with UV Filter and Cover 2Set