This Thousand Oaks SolarLite full aperture solar filter is designed for telescopes with an outer diameter of 286-290mm. SolarLite film is durable and safe to use and produces a yellow-orange view of the Sun. Exceptionally clear and high contrast images make SolarLite a joy to view and image through. ** Due to high demand for the 2017 Total Solar Eclipse, orders placed after 7/9/17 may not be able to be delivered in time. If we cannot fulfill your order in a timely manner we will contact you about an alternative. **