The one that slides over (and occasionally has a zip tie) like the original one.
The one that screws in instead of the metal spacer at the corner.
This design is like the original one (slides over, but you also unscrew the spacer and insert it in the mount's hole. Then you screw in the spacer after sliding in the mount. This way your bed still rests on a steel spacer, but you don't need zip ties to fix the mount.