Bumper height

Okay so the rules I can find say, “BUMPERS must be located entirely within the BUMPER ZONE, which is the volume contained between two virtual horizontal planes, 4 in. above the floor and 12 in. above the floor.”
But I’m questioning myself and what I read, because why would the base that they gave us be only 2 in. off ground at the bottom. So, are we supposed to use brackets to keep them within the range that they say. Could someone please help me out a bit

You may modify the base using standoffs (or risers).

So brackets would be necessary if you planned on using the kit chassis with no modifications. As long as the bottom of your bumpers are not less than 4" off the ground you will be OK.

A couple of years ago my team used a custom chassis, but the bottom of it was only 1" off the ground. We used brackets to lift the bumpers into the bumper zone.

Oh, okay. Thank you for that. I was worried so that clarification helped out.