For the 2013-2014 season, Anon came out with the M2. As an alternative to the smaller M1, it offers a frameless look, a slightly larger fit, and an increased field of vision, while still employing the same Magna-Tech construction. Furthermore, due mainly to its rimless frame design, the M2’s lens swap procedure is even simpler than the M1’s.
I’ll start with a rundown of the construction of the M2’s lens-to-frame magnet interface (compared to that of the M1’s), and its super-simple lens change procedure.
Lens Change Functionality (M1 vs. M2)
The M2’s lens is retained by eight neodymium magnets: three on the top, three on the bottom, and one on each side of the frame.
Each of the M2’s eight connection points (created by the eight magnets on the frame and eight on the lens) has a pull-force of 2.75 pounds. That means the total retention value between the M2’s lens and frame is 22 pounds. So unless you pull something in the neighborhood of 75 Gs, there’s no way the lens is going to work itself away from the frame.
Even if you were to experience a serious digger / face-plant on hard snow, I would honestly still be surprised if the M2’s lens came completely free from its frame, especially given the kind of precise prying technique it takes to remove the lens by hand. If it did, I don’t think the whereabouts of your lens would be the first of your worries.
In my mind, lens retention simply isn’t a point of concern with either the M2 or the M1.