To begin, I want to make it clear that the distinction between regular, XLJ, and XL refers to to the size of the lenses. No frames
Making this difference is crucial.
Although the frame size may be same across many models, the lens sizes available for each frame may vary. By way of illustration, if you bought a pair of Oakley Flak Jacket XLJ sunglasses, you would get a pair of Flak Jacket frames with XLJ lenses already attached.
If your sunglasses exclusively mention Flak Jacket on the packaging, it means they arrived with regular lenses.
Within a certain design of frame, both regular and XLJ lenses may be used.
Compared to prescription lenses, standard lenses are shorter from top to bottom and have a more rounded bottom.
The bottom of XLJ lenses are carved in a wave pattern, making them longer overall. Compared to regular lenses, they provide a wider field of vision.
Oakley's Half Jacket and Flak Jacket goggles are compatible with XLJ lenses.
In the same way as XLJ lenses are longer than regular lenses, so are XL lenses. Lenses marked with the XLJ and XL designations are not interchangeable since they are designed for separate frame frames.
Standard and XL lenses are compatible with the same frame.
Half Jacket 2.0, Flak 2.0, Bottlecap, Fast Jacket, Radar, and Radarlock are all available with XL lenses.
In conclusion, the key distinction between these lenses is one of size and form. Either the standard or its extended relative will work, provided the suitable frame is used.
Don't hesitate to post a photo of your lenses in the comments or contact our support staff if you're considering lens replacement but are unsure of the exact model you have. You can count on us to help you out.
All lenses except Radar and RadarLock may be switched between XL and normal sizes. Only the Radar XL and RadarLock XL frames are compatible with XL lenses due to the frame of the nose piece. It's also worth noting that regular lenses won't work with an XL frame.