I just purchased a previously used HMH tube fly tool kit. Included was a tool/piece I'm not familiar with...but it appears to be a tube tying adapter. It's on the right in the photo. HMH large plastic tube material is a perfect fit at the tip. The only threads I see on the unit are in the brass hole on the side, which would seem to hold a set screw. No threads are in the silver/nickel end.,,so I'm not clear on how it is to be attached to a vise...or what vise it was made for. Any ideas?