ARC'TERYX Alpine Backpack Alpha FL 45 This discontinued item is a rare, ultra-lightweight 45L pack from ARC'TERYX, suitable for overnight camping. I've used it on about 20 mountain trips. I'm selling it because I've switched to a different backpack. As the photos show, there are some scratches and dirt from use, as well as areas where the seam tape has been repaired, but it should still be perfectly usable.