With a sleek and robust design and an eyecup that can be adjusted by rotating, these eyepieces are designed for comfortable and user-friendly observation. They also feature a 60-degree field of view and six-element, fully multi-coated optics. The X-Cel LX eyepieces are parfocal, so you won't need to refocus much or at all when changing eyepieces. Focal length: 5 mm. Field of view: 60 degrees. Eye relief: 16 mm. Coating: Fully multi-coated. Barrel size: 31.75 mm/1.25 inches.