82° 4.5mm LER Waterproof EyepieceFeatures With its particularly long eye relief of 15. 9mm, the 4. 5mm LER ocular from Explore Scientifics 82 Series of Argon Purged Waterproof Eyepieces puts the focus on a comfortable viewing experience for all observers. A long eye relief is especially important for eyeglass wearers because it allows them to enjoy the full field of view. The 4. 5mm focal length is perfect for observing objects that would benefit from high magnifications such as the