This part allows you to mount the filament on the side of the Lulzbot mini. It uses the same arm that the printer came with for the filament to sit on, but attaches it to the side. The right side mount bolts onto the same location as the factory arm, but the left uses a hook to sit on the printer. I personally needed to do this since my printer is on a rack without enough room on top. Below is the recommended hardware to use:
Right side mount:
M5 x 25mm bolts (2)
M5 lock nuts (2)
M3 x 14mm bolts (2)
M3 lock nuts (2)
Left side mount:
M5 x 25mm bolts (2)
M5 lock nuts (2)

LulzBot

Mini

Doesn't Matter

Doesn't Matter

If you are using a full roll of filament, the filament may try to pop off the roll when the head moves toward the roll if the filament is mounted horizontal. Mounting it with the angled slot will prevent this or having some kind of filament guide.
Also, over tightening screws could cause plastic to crack if printed with layers parallel to base.