They screw in to the aluminum insert and then your broad head can glue onto the steel insert.
The website says it is under reconstruction and when i try to call the ph# i posted it is always busy, i have bought stuff from Archey Past before, but i may have to go to 3 Rivers, as i need some more of the steel inserts, i am pretty sure that 3 rivers carries them also. Hunt'in Season right around the corner...