Farpoint SSF-255 Solar Filter — 250–255 mm Telescope TubeThe Farpoint SSF 255 Solar Filter is designed for telescopes with 250255 mm tube outer diameter. ISO 12312 2 certified solar film blocks 99. 999% of harmful UV and IR radiation, delivering a sharp, natural color white light view of the Sun, sunspots, transits, and partial eclipses. Specifications Fits telescope tube OD: 250255 mm (9. 8410. 04) Filter outer diameter (Mask OD): 259 mm (10. 20) Clear aperture (Mask ID): 209 mm (8. 23) Construction: Laser