Small ID Line SI Bushmaster powertube, untested, used. Not sure if this cup seal will seal. See photos, untested. Stock from a Line SI Bushmaster. Probably about a 0, 1 or 2 size power tube. Will result in a lower velocity since not as much air can flow. Standard Nelson specs, will work on Nelspot 007, Line SI Bushmasters, Lapco pump, wintecs and other standard spec nelson pumps.
