Clevis or D-ring
D-rings are basically rings in the shape of a D that are attached to a trailer or truck by a bracket that looks like a piece of tube cut in half and fit over the flat part of the D-ring. it is then welded (some are bolt on but they are not rated for heavy loads)
http://www.all-trailer-equipment.com...ing1inDia.html
clevis/shackles are attched to trailer/truck by a piece of solid steel plate with a hole in the middle and welded in the desired position. the shackle/clevis is then bolted on using the provided
http://cache1.pirate4x4.com/tech/bil...y/Shackels.jpg
hope that helps
-cutts-



