This large-area backing plate has industry-standard 7/16-20 UNF female threads to accept a standard seat belt mounting eyebolt (sold separately). It is FIA-Approved for mounting driver restraint harnesses with snap-in end plates.
No welding required. Simply drill a 7/16" hole in the floor pan and sandwich the floor between the eyebolt and this plate. A #10 hole (0.195" / 5mm diameter) lets you add an anti-rotation screw or rivet (not included) if desired.
The square plate measures 3mm Thick x 65mm Long x 65mm Wide (1/8" Thick x 2 9/16" square) for over 4200 square millimeters (6 1/2 sq in) of surface area to resist pulling through a sheet metal floor. Sold individually; one required per eyebolt.