5 inch Black anodized tube made from 6061-T6 Aluminum with 2.5mm thick sidewalls to withstand heavy stress. T6 level heat treatment. The tube OD is 43mm, ID is 38mm.
This is for the tube only without end cap, cups, or fitting
It nice to have a couple extras (at this crazy price) in case of mishaps in the field. Easy to change out internal from another filter kit into a clean tube. :)