Made this to be able to print nylon and other hydroscopic materials. Also it means I no longer need to reach down into the printer to get at the two rolls for the middle tools, which was always a pain. I have extra caps I didn't drill holes into, so when I change filament the cap with the tube stays with the printer, and the airtight dry box with the old filament and unmodified top goes on the shelf. a much nicer system than the ones I see where they drill into the box itself and need a ptfe tube for each dry box. One thing I wish the toolchanger had was regularly spaced tapped holes. For a printer meant to be experimented with, it sure has a dearth of mounting points. Yes, I know it is completely blocking the power supply fan, I have a plan for that.