A threaded piece (internal; various sizes) of material inserted through a hole (usually sheet metal or light gauge) that is rivited in place by squeezing the insertion tool handles. Montreal; avialable? Look in the yellow pages under, "Industrial fasteners."
think of it as a rivet, but with a threaded center. best i can describe it. locally? i dunno. got a fastenal store? trey
http://www.zygology.com/products/tier2.asp?category=threaded inserts This will give you an idea of what they are and what they do. john
also called rivet-nuts . i have a Marson that i bought at the local Napa store they are installed with this tool: