Size = 8-32 x .625" STI SHCS T20 Hexalobular Bit (Included) Head Diameter = .315" Head Length = .190" PreCoil Socket Head Cap Screws are purpose-built for STI (Screw Thread Insert) tapped holes — the oversized internal threads you cut before installing a Heli-Coil.
Instead of running standard threads, only to later blow-out to STI sized,