based on this thread viewtopic.php?f=1&t=76193&st=0&sk=t&sd=a#p696119
I added o-rings to both my Swift LT and Swift FX masks. wow what a difference, really got the leak line settled down. I gave up on the Swift FX several weeks ago because I couldnt control the leaks with it. Last night i put o-rings on both and immediately noticed the difference with the LT. I woke up in the middle of the night and switched masks just to see if the helped and the FX even had a decent leak line.
I highly recommend this to anyone who is having leak issues. It is a cheap option to try before buying a new mask.