The PENTAX XW 40 eyepiece is exclusively designed for telescopes that feature a 2 inch focuser. Within its JIS Class 4 weather-proof construction, this high-performance eyepiece features high-refraction, low-dispersion lanthanum glass elements and PENTAX-original multi-layer coating for bright, high-resolution images with minimal aberrations and distortions. It offers a focal length of 40mm, long eye relief (20mm), and a 70 degree apparent angle of view.