1. High quality-using industrial-grade aluminum and advanced optical lens design to capture photos and videos with amazing clarity and detail. 2. Dual split-screen lens mirror video effect-when the teacher puts his hands together, participants will be to see a complete panorama of the piano keyboard, and participants can still see each finger on the note at close range through the mirror video. Students, students/participants The reader sees it in the expected way. 3. Universal design-the lens is suitable for most mobile phones with a camera lens diameter of no more than 13mm, such as for , , and other smart phones or even tablet computers. 4. Wide-angle hemisphere image--The wide-angle lens projects a super large range, you can see the full-key bracket without standing, with higher definition, and can be greatly expanded to 180 field of view, such as crowds, buildings and landscapes. 5. Portable and detachable-easy to carry when traveling and hiking. The lens is easily fixed to your phone with a soft rubber clip that will not scratch or damage your mobile device. Improved the length of the clip to more stable on the phone. Product name: Piano Sparring Lens Features: dual-screen, full-key, distortion-free piano online teaching special lens, art online teaching fisheye lens, painting online teaching super wide-angle lens Advantages: more high-definition, larger angle, no need for brackets to see the full key Material:ABS+metal colour:Black Package Contents: 1 x Piano sparring fisheye lens Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.