Pentax 70531 SMC-XF 8.5 1.25-Inch Eyepiece for Pentax Spotting Scopes Designed for use with our 65mm scopes High-refraction, low-dispersion lanthanum glass elements to provide high-resolution images with minimal aberrations Pentax-original smc full-surface multi-layer lens coating to improve light transmission efficiency Advanced computer simulation design technology was used to drastically reduce internal reflections producing brighter, clearer images JIS Class 4 weatherproof construction make these eyepieces more durable and water resistant