You are Bidding on 4 (FOUR) D ring tie downs. These are the same D rings I install in the trailers I sell, when I set them up for Holding down Motorcycles, Lawn Mowers, ATV's, ETC. Not for Cars or other heavy equipment
Each ring is rated to 1200# and measures 5" long, 3.5" wide, and 3/8" deep (they are larger than they look in the picture!).
I use a 3" hole saw to cut a hole part way into the floor (3/8" down) then use a chisel or screw driver to "pop" the wood out of the hole, then drill 3- 5/16" holes through for the Carriage bolts(not included). I usually install right on a frame cross member for a strong mount.