The best thing about this eyepiece is that can be use for day time viewing also, unlike the Naglers that have pincushion distorsion bending straight objets. The Vixen Superwide have an ultraflat field of view to the edge. The optics are in perfect condition and the barrel shows normal wear. The 9MM Nagler type-1 or type-6 have more field of view but the field of view in this eyepiece if more flat and also have better color correction. Whit the 4X powermate is a excellent planetary eyepiece with 20MM eyerelieve.