In hand Help!

[DanniRenske]

I went to a show recently and I saw a horse in an in hand class in blinkers, side reins and what looked like a lunge roller.
Could anyone tell me what this is for? I have never seen it before, is this what would be called a harness as a lot of classes near me say not to be shown in harness.
Or is it for a specific class ie driving type as I am thinking of starting to show in a driving type class.

 

[Elf On A Shelf]

I'm guessing it would be a driving type class. Native stallions can also be shown in a stallion harness.