The enhanced fully multi-coated CEMAX™ 2X Barlow Lens. 1.25" Barrel Size. Specifically designed for use at H-alpha (or Ha) wavelengths, this Barlow uses optimized coatings to enhance contrast, minimize glare and also affords excellent contrast for planetary viewing. With caps. Please note that this Barlow is NOT a filter and for solar observing must be used in conjunction with a Coronado Ha Solar telescope or telescope with a Coronado filter set appropriately and safely mounted.