Ready-Rail Snap-On D-ring attaches directly to the rail uprights on PJ utility trailers, on either the inside or the outside. Each ring includes a beefy lockable through-pin with a retaining clip, and is rated for 1,275 lbs. Sold as each.Specifications:

3 Inside width
Wide design accommodates variety of tie down styles
1,250 lb. working load limit
Includes 1/2″ x 4.75 pin with clip
Designed specifically for the PJ Ready Rail system