Not sure about the one Primos is promoting, haven' t seen it yet. There is one out called Hunter' s Shooting System that is basically a full boddy harness sewn into a vest. If it has the crotch straps you can pretty well assume that it' s this type. This is not a cheap upgrade from a chest harness. It' s a good improvement on a full harness. The vest makes it much easier to put on and remove since it keeps all the straps from getting tangled. All you do is put the vest on, clip the wasit or chest backly and hook the crotch straps. Clean and simple.
I' ve used the SOP harness for four years now. Greatest improvement to safety in decades. The vest is a godder system and mine is on order.