Vanguard MARS 1 Plate

All what you need is 1/4" D-Ring. I mine has these specifications:

The length of shaft: Approx. 10.5mm/0.41inch

Total length(include base): Approx. 14.5mm/0.57inch The diameter of the screw head: Approx. 11.5mm/0.45inch The diameter of the D-ring head: Approx. 16mm/0.63inch