Drybox filament feeder with filter (PC4-M6)

Update 10-nov-2018: improved the inner cap design and added an outside cap to close off unused feeders. Also included a 45 degree design

This is my take on a drybox feeder. I wanted a solution where the inside of the box is isolated from the outside, while still feeding filament. This is accomplished by inserting a sponge in the inside part of the feeder, and screwing the cap on while inserting filament. It's also possible to put some oil (WD40) onto the sponge to lubricate the filament a bit