Pentax 70516 SMC-XW 20 1.25-Inch Eyepiece for Telescopes and Pentax Spotting Scopes Improved 70 degree field of view for easier viewing XW 7, 10, 14 , 20 will give a wider field of view than our previous eyepieces when used on Pentax Spotting Scopes or with telescopes XW 14, 20, 30, and 40 are designed specifically provide ideal viewing conditions when used with a telescope Fully multi-coated lenses increase light transmission and color quality High-refraction, low-dispersion lanthanum glass elements deliver bright, high-resolution images with minimal aberrations and distortions