ACTUALLY - it might be only the reins. I just went back to the page. It's says "Specialty martingale rein made in durable and long lasting Camelot leather." Maybe give them a call tomorrow since the title does say "set".
Sorry, I'm at work and was just kind of glancing at the ad title the first time...
It is the same thing as a German martingale - just that originally it was just called a Market Harborough ( after a town in England )
As you can see from some adverts they are now calling it martingale reins - it makes life very confusing when a piece of tack ends up with three or four names because some whole-seller can't be bothered to label things properly - the worst thing for confusing and multi-names are bits , e.g. Bubble snaffle / dutch gag / english gag / 3 ring gag /3 ring snaffle / pessoa elevator bit ( all the same thing ) - I swear that every time I open a catalogue it has a new name.