Farpoint SSF-397 Solar Filter — 392–397 mm Telescope TubeThe Farpoint SSF 397 Solar Filter is designed for telescopes with 392397 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. SSF 397 is a specialty SKU at the upper end of the Farpoint SSF line, sized between grid points to catch large aperture telescopes that fall outside the standard 5mm grid.