The focusing mask takes the guesswork out of focusing and even overcomes conditions, quickly and easily giving your telescope the best focus. Made of aluminum alloy, it can be used for a long time, and it's not be a burden to keep the telescope balanced. Applicable to all kinds of telescopes, refractors, etc. Features - Material: Aluminum alloy - Color: Black - Diameter: 9.50 x 9.50 x 0.10 cm / 3.74 x 3.74 x 0.04 inches - Note: Suitable for telescopes with an outer diameter of about 63-89 mm / 2.4-3.5 inches - Fast focus: The focus mask is designed to help you focus quickly. take the guesswork out of focusing and achieve perfect focus in seconds. - Protect telescope: The focusing mask has scratch-resistant silicone sleeve screws to protect your precious telescope surface from scratches. - : Made of aluminum alloy, it can be used for a long time, it's light, and will not be a burden to keep the telescope balanced. - Highly compatibility: Suitable for all kinds of telescopes, mirrors, refractors, etc., please pay attention to whether the size is appropriate before purchasing. - Easy to install: Easily attach to any telescope via screws for perfect focus, making focusing for astrophotography an easy task. Package list: 1 x Focusing Mask