PiesangKop_ZA
I am Jim Jannard...
This is a useful article on the various generations:
www.revantoptics.com
The History of Oakley M Frame Sunglasses | Revant Optics
Introduced in 1989 as the Mumbo, the M Frame has long been a staple in the Oakley line-up. However, the iconic frames have seen some tweaks over the years.