Review on 🔒 DC Cargo Mall 10 D-Ring Tie-Down Anchors | Heavy Duty 3/8" Steel D-Rings for RV Campers, Trucks, Trailers, Boats, Vans | Secure Tie-Downs for Kayaks, Motorcycles, Deliveries, ATVs by Jeffrey Dunn

They're big and strong. Note the rectangular knockouts for the bolts. otherwise if you want to secure them with 3/8" carriage bolts you will probably need washers as shown in the pictures (July 2016). The "D" ring is about 3/8" and you will need it with Mount 3/8" screws to get full mounting strength. The 1/4" or 5/16" carriage bolts are too small and twist in the square mounting cutouts. I want the square mounting cutouts to be visible in the picture If the picture was better and I could mount them with 3/8" carriage bolts that would be a 5 star situation. In my case I had to because of my application where I can't get to the back of the mounting surface can, mount with 1/4" screws and washers. I only have a 20 TPI 1/4" thread that I mount to. In my case, smaller tie downs with round mounting holes would be better. I could show this better in a picture. 3/8" square head screws would be an intermediate head to clarify this as well .