1. Improvement of the contrast of images of observed objects 2. Can be used not only for astronomical observation but also for astrophotography 2. Ideal for observing faint and low-contrast deep-sky objects 3. Significantly reduces light pollution, ideal for urban and suburban observations 4. Material: optical glass lens, aluminium frame 5. Thread: standard M28.5 x 0.6mm 6. Diameter of lens barrel: 1.25 inch 7. Net weight: about 5.2g
