This Screw Is Hardend & High-strength To Install Into Concrete.INSTALLATION INSTRUCTIONS 1. Wear Glasses And Choose The Correct Drill Bit To Drill A Hole, The Hole Suggest To Be 3/16” 2. Use The Air Blow To Clean Hole 3. Install The Screw Point Through The Fixture Into Hole 4. Continue To Dive the anchor firmly Against The Fixture.