Product description Key benefits Secure, adjustable mounting for connecting a mobile device to optical eyepieces. Fast, tool-free setup: expand the eyepiece bayonet, align, then lock in place. Stable hold that prevents slipping during photo or observation sessions. What it is and how it works Eyepiece bayonet: inner diameter adjustable between 22.5 mm and 48 mm to accommodate a wide range of eyepiece sizes. Rubber suction cup: attaches directly to your mobile device to create a firm connection between the phone and the eyepiece adapter. LOCK CLASP: turn the eyepiece bayonet clockwise or counterclockwise to expand the bayonet to the required size, then press up to fix the eyepiece bayonet in place and secure the connection. Compatibility and performance Fits eyepieces with inner diameters from 22.5–48 mm. Designed to link a mobile device (via the rubber suction cup) to optical eyepieces for stable imaging or viewing. Simple mechanical lock provides reliable holding force without electronics or tools. Practical applications Use your mobile phone to photograph or record images through a microscope eyepiece for documentation or teaching. Attach a mobile device to a telescope or spotting scope eyepiece for astrophotography or birdwatching images. Pair with binocular eyepieces or field optics to capture reference photos during fieldwork or inspections. Operation tips Center the rubber suction cup on the mobile device and ensure a tight seal. Place the expanded eyepiece bayonet over the instrument eyepiece, then turn clockwise or counterclockwise to reach the correct diameter. Press the LOCK CLASP up to secure the eyepiece bayonet and confirm stability before use. Includes only the described components and functions: adjustable eyepiece bayonet (22.5–48 mm inner diameter), rubber suction cup for mobile device connection, and the LOCK CLASP mechanism.