Farpoint SSF-170 Solar Filter — 165–170 mm Telescope TubeThe Farpoint SSF 170 Solar Filter is designed for telescopes with 165170 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: 165170 mm (6. 506. 69) Filter outer diameter (Mask OD): 174 mm (6. 85) Clear aperture (Mask ID): 124 mm (4. 88) Construction: Laser