The M8-35B is a white steel zinc bolt that is needed to assemble brackets. (x4) bolts are used to fix 4-inch casters to Flexpipe structures. This part cannot be used for anything but the assembly of the four inch brackets. To create the a bracket set, you need to connect one WF-UP and one WF-LOW with two M8-35B and two M8-N nuts. (you will need two sets for every caster). This has been improved over the years to be easier to install on Flexpipe structures, however, be sure to check the installation steps for the W-4PSB, W-4PF casters to see how to use the M8-35B.