this is the thingie I use for the front axle. You won't actually need it if you tighten the left pinch bolts before you torque down the axle nut (per manual),
but there's a "single wrench or two wrench" argument associated with tightening the right pinch bolts instead, and leaving the left pinch bolts loose until after you bounce the forks to set the front axle. The hex thingie does make it easier to adjust the position of the axle laterally in the forks.
You might read Cracker Jack post
here on which fork to keep loose when you bounce the forks to set the front axle.
