The Prusa USS Drybox (Universal Storage System) is an airtight filament storage box built around several clever design features. Its unusual central opening allows the box to be mounted directly onto a spool holder while also minimizing the free internal volume where humid air could accumulate. Our internal testing shows it performs exceptionally well even without silica gel, which can still be added or replaced through a dedicated side door.

The body is made from hydrophobic polypropylene (PP), a material significantly less permeable to moisture than the polycarbonate commonly used in other dryboxes. The rubber cap features a special slot that holds the filament, enabling you to pull it out without opening the box—greatly reducing the exposure to humid air and simplifying everyday use.

The drybox is also stackable, making it easy to store multiple spools. The idea is simple: place the spool inside once and leave it there until you’ve used it up.