15mm focus length eyepiece. 15mm is a intermediate eyepiece fit for observing the lunar surface planets binaries and bright nebula interior. 4 Lenses in 3 Groups: Multiple group lens combination to improve optical performance; the eyepieces delivers sharp images with good color correction and contrast. 16mm eye relief: Generous 16mm eye relief allows comfortable viewing distance and lets eyeglass wearers see the entire field of view. Full multi coated optical and 4-elements in 3 groups allow more light pass through to the eyepieces thus providing a brighter sharper and higher contrast images. SVBONY universal cell phone adapter mount makes it easy to position a point and shoot for high magnification photography. Make your mobile phone into a video camera and images capturer; so that you can explore the nature world easily through the screen. You can connect cell phone adapter to tripod if you need. For example,if you have a pocket monocular or binoculars,and you want to pictures or videos,then you can connect it to a tripod. Steps to install the phone: 1.Pull the phone support plate to the maximum (3.93in wide). 2.Put the phone in to fix it. 3.Turn the screw under the phone support plate to adjust the phone so that the camera of the phone is aligned with the eyepiece.