Set-Rite - 2-1/2" Stainless Self-Tapping Screws 2-1/2" Stainless Steel Self-Tapping Screws For Use on Cast Iron Toilet Flanges and metal lipped flanges. Use with our Code Approved Extender to raise flange to the correct floor height Use on Cast Iron, Lead Bends, PVC & ABS Flanges or Uneven Surfaces