Good God. Wouldn't it be sensible for Extreme to extend the post length about a foot so the rack fit's like TrimmerTrap racks do? Jeeze, this is stupid. Bolting the racks to the top of a flimsy rail is a stupid way to do it anyway. FAIL.
The way these racks secure the trimmers is the absolute best way to do it. But the rest of this rack is a poorly engineered piece of junk. You have to buy supports to keep the racks from snapping the power heads off and then completely re engineer the rack mounting system to keep the racks from snapping off of the trailer and destroying the trimmers.