You are buying four (4) NORS Auveco fasteners. It is a 1/2-13 x 1-3/4" long stainless steel capped, high crown (domed) head bumper bolts & stainless steel lock washers and nuts. These bolts have a 1.000" head diameter.
Please note that the shoulder under the head is 3/16" (see photos).
The heads are not show polished but I did clean them and they are very nice.
