These tabs are made to weld to any flat surface.  These tabs are 3/8" thick and have a 1/2" bolt hole.  We offer three different lengths so that you can mount your joints in a neutral position to maximize axle articulation. Long tabs are 3 ¼" from bolt hole to the surface, medium are 2 3/4" from bolt hole to the surface and short are 2 ¼" from bolt hole to the surface.  Like all of our products, they are made in the USA from USA steel.