1 Minute to Set UpAdopted Unique Design that is easy to align eyepiece and phone camera. You just need to take less than 1 minute to set up that save your Time and free your hands. Fits Wide Range of EyepiecesThe universal phone adapter mount(with 3 additional rubber rings) is suitable for eyepieces with 28mm-39mm(1.10-1.53) outer diameter and can be mounted almost of binoculars, monocular, telescopes, spotting scopes, Microscopes. Compatible for Almost All PhonesUniversal mobile phone adapter bracket with a large width range: 55mm-85mm(2.16-3.34), Suit for more than 99% of Smartphone brand models! Commonly used in iPhone, Huawei, Samsung,LG, Sony and so on. Unique DesignThis phone photo Mount adopts unique design allow user to adjust phone holder position to avoid Phone holder part press Phone volume & power keyboard to take picture constantly or turn off phone. Installation guidance 1, Stretch out the clamp, place your phone in it and then loosen the screw on the clamp. 2, Align the center hole perfectly with your phone main camera, tighten the screw on the phone clamp. 3, Attach the adapter to the eyepiece and fasten the screw sitting under the eyepiece cup. 4, Double check to make sure your phone is tightly held by the clamp and adapter is stably attached to the eyepiece of your optical instrument.3 sizes rubber rings Compatible with eyepieces whose outer diameters are ranging from 28mm to 39mm. Better fit for different sizes of eyepieces and not easy to fall off any more. no scratching but tighter holding Using soft sponge material on the clamp body and non-slip rubber on the clamp side can better protect your phone from falling off or getting scratches. Quicker and easier focus Adjustable phone holder enables you to align your phone camera to the eyepiece in a short time period without touching phone side buttons.