These self-clinching flush head studs are installed by placing them in properly sized holes in the sheets and squeezing into place with any standard press. The squeezing action embeds the head of the stud into the sheet. Flush head studs are for sheet thickness of .040" and greater. Type FH is recommended for use in steel or aluminum sheets HRB (Rockwell "B" scale) 80 or less and HB (Hardness Brinell) 150 or less.