Celestronengineered theirLuminos Eyepiecesto provide you with a comfortable 82° field of view, and made the entire series parfocal, allowing you to change it out with other Luminos eyepieces without having to adjust the focus. This allows you to spend more time viewing while reducing the chance of hitting the scope out of alignment. This model features a 7-element lens configuration and is fully multi-coated to improve image brightness and contrast. Its 1.25" diameter barrel fits the same size drawtube or accessories and has machined filter threads to accept eyepiece filters. Made of a lightweight and durable aluminium alloy with an anodized finish, the body has a slip-resistant rubber collar and an innovative retractable eyecup that pops up when you need it and drops down when you don't with a simple twist.