My first sewing project was a pack cover for my wife’s new Osprey Atmos 50 AG pack. It’s cut from two yards of MEMBRANE silpoly PU4000. The Side panels are 30”x12” and the center panel is 12”x54”. After sewing the panels together, I installed a grommet near the edge of the cover and then folded the end and sewed it to create a 1” channel for shock cord. I installed shock cord and a mini cord lock to secure the cover to the pack. It fits as well as any cover I could have bought and only weighs 2oz! Can’t wait to start my next project!!