This listing is for FOUR (4) heavy duty surface mount tie down attachments and four (4) hardware kits. Each solid steel d-ring has a 12,000 lb. rating (straight pull). WLL is 4,000 lb. capacity*. *WORKING LOAD LIMIT: The maximum load weight a tie-down should be subjected to during normal use. To assist in making the proper tie-down choice the Federal D.O.T. requires the W.L.L. to be 1/3 of the Rated Capacity. HARDWARE: This listing includes 4 kits. Each kit comes with 2- 3/8" x 2-1/2" long carriage bolts, 2 - fender washers, and 2 - 3/8" nylon locking nuts. If the listing isn't a PRIME order you may request 1.5" long carriage bolts by sending us a message. DIMENSIONS: Please view the diagram in the photo gallery, or the 1/2" diameter ring measures approximately 3.5" wide x 3.5" long. The "top cap" measures 2" wide x 3.25" long, with 7/16" square holes on 2" center designed to receive 3/8" carriage bolts. OPTIONS: This tiedown is also available without the hardware and also available with heavy duty backing plates. Search in our storefront or send us an email for a direct link. This listing is for TWO (2) tie down attachments, backing plates, and 2-1/2"L hardware kits. Hardware Kits = 8 - 3/8" x 2-1/2" long bolts, 8 fender washers, and 8 nylon locking nuts. The heavy duty d-ring has a 12,000 lb. vertical pull weight rating*. The ring and backing plate are zinc coated to inhibit corrosion. These surface mount D-rings are also available without Backing Plates. The backing plate is used for support under the floor when installing the attachments, and prevents the bolts from pulling through. *RATED CAPACITY: Also known as "assembly capacity" or "break strength" is the minimum load a complete assembly can withstand before failure in a laboratory pull test when the product is NEW. WORKING LOAD LIMIT: The maximum load weight a tie-down should be subjected to during normal use. To assist in making the proper tie-down choice the Federal D.O.T. requires the W.L.L. to be 1/3 of the Rated Capacity.