SP series eyepieces set the performance standard for modern telescope eyepieces. The proven 4-element Plössl design offers edge-to-edge blackened elements with the highest contrast images possible. SP series eyepieces minimize spherical aberration, distortion, astigmatism, and oversized white optical elements provided by the observer. Stray light is eliminated with the fold-back rubber eyepieces standard with every SP eyepiece and all but the three lightest models feature the security of rubber grips.