The 2-group 4-element Plossl design of Vixen's NPL Series delivers bright, sharp views with high contrast and good colour correction. The 20mm, 25mm, 30mm and 40mm models feature twist-up eyecups. All have fully-multi-coated optics. Affordable eyepieces that offer a noticeable improvement over generic Plossls supplied with most telescopes.
"The Vixen SSW eyepieces produce excellent views and their build quality is beyond reproach, making them an excellent choice for intermediate to advanced observers, but beginners may struggle with eye placement."Steve Richards writing for 'BBC Sky at Night' magazine May 2016.