This is to hold the pump for the reusable vacuum bags for storing your filament! I got tired of it rolling around in my drawer. If you don't have one yet, these are great and easy to use! And now you can store your pump into this fancy gridfinity holder! Link below for amazon product. Just throw your filament roll into them when you aren't using them, add some desiccant (silica beads or whatever you want to call them) https://a.co/d/azalNvO