These mounts were designed for the Rola V-Tex or Vortex Roof Rack/Basket. I designed them to mount my recovery boards, but because they can be positioned anywhere and have a slot for the mounting hardware they could be used to mount just about anything (high lift, shovel, rugged cases, etc). They were designed for 5/16th inch hardware (nuts and bolts) but M8 will work as well. Be sure to print these pretty solid for lots of strength and don't use these to mount anything excessively heavy.