M4 is M4. If they change the form factor of the lens, they'll give the goggle a different name.
The biggest thing you want especially for us Aussies is a lens for bright conditions ie low VLT and a lens for whiteout/low light conditions ie high VLT.There's another thread around here somewhere in which people argue about their favorite lens color. I think the takeaway is that it's very individual. For me, the VLT% is way more important than the color.
Understood and thanks again for the reply but the other lenses that I have for the m4 are for brighter conditions (sunny and a variable lens). I am trying to figure the best option for a poor light / white out day lens which I can take out, and given that access to stock of lenses on the UK is very limited 😖 I am scratching around for best option. One option is old season amber lens and another is the infrared again from previous seasons…I've taken to carrying a spare lens in my backpack so I can swap if necessary. The whole point of the M4 is how easy that is to do.