These are weld-on brackets for the rear axle to relocate both shocks behind the axle. There are 4 pieces for the axle (cut for a 10 bolt rear), and 4 pieces for the factory tube behind the axle per kit. They are 1/4″ thick laser cut mild steel and the 3 mounting holes are 1/2″ diameter. This is designed to give maximum flexibility when relocating the shocks.
For the included hardware option, it is recommended to use a wood 2×4 to properly space and align the brackets during installation. The hardware includes 4x grade 5 1/2″x3″ bolts, 4 washers, and 4 flanged nuts and is intended to support mounting the brackets 1.25″ to 1.5″ (recommended) apart. The long sides of the brackets should be welded flat/parallel to the frame/ground.
Completely vertical is not always the best way to mount shocks Being able to angle them lets you trade dampening force for total travel distance. The Viking shocks I recommend (and sell) are able to produce plenty of dampening force so you can tune your rear shock setup to do exactly what you want. The top brackets fit up high near the bed and the lower brackets fit near even with the lowest point of the differential so you have the maximum room available.