Osprey StraightJacket Compression Sack

The rectangular shape is designed to eliminate the awkward, rounded bulk that often creates dead space in your pack. By compressing your gear into a stable, brick-like shape, these sacks stack efficiently, allowing you to maximize every inch of your backpack's volume.

They are constructed with water-resistant fabric and sealed seams, which provide excellent protection against rain and moisture. However, because they use a zippered closure rather than a roll-top, they are best described as highly weather-resistant rather than submersible.

The compression wings wrap around the sack and use adjustable buckles to cinch the contents down. Once you have packed your items and zipped the bag, you simply pull the straps to tighten the wings, effectively minimizing the overall volume of your gear.

The 8L size is ideal for smaller items like extra layers or a lightweight down jacket. The 12L and 20L options are better suited for bulkier gear like sleeping bags or larger clothing kits, depending on the loft and compressibility of your specific items.

Yes, the sack is built from 40D nylon ripstop, which balances lightweight performance with necessary durability. It is designed to handle the friction and pressure of being compressed and packed repeatedly without tearing.