K&F CONCEPT Magnetic Lens Mount & 58mm Variable ND2-32 Filter for iPhone 17 Pro
【Double-sided Magnetic 】 There are 17 strong neodymium magnets on the front and 8 on the back, all of N52 grade, providing a strong suction of 2500gs (about 8N). It can be adsorbed quickly and stably without falling off easily.