1. Ultrasonic welding technology, without any glue 2. Q elastic silicone ear, high temperature resistance, no peculiar smell 3. High-definition PMMA lens, explosion-proof and shatter-proof, good light transmittance 4. Non-slip handle for easy grip 5. Material: food grade silicone + ABS plastic + PMMA lens 6. Multiples: 3 times, the thickness of the center of the lens is 14.5 mm 7. Diopter: 800 degrees 8. Lens size: 75mm 9. Focal length: 3-7.5cm 10. Interpupillary distance: 3-20 cm 11. Weight: about 70 grams 12. Length: about 22 cm