First off we need to see what this really is and then break it down. It is a Safety Bar Squat off a hassock with a close stance. This is to work the upperback and glutes. Then a neck harness we added in a attempt to keep the head up. Finally weights and kettle bells were added (hanging from bands) to each side to add a stability (almost vibration) effect to the bar.
If you do this get ready to be tossed around some. I would suggest starting light as pictured and work up as you feel more stable. When you unrack the bar give yourself a second or two before you squat (the bells will be moving like crazy). 5-6 reps is enough for this one.
Good Luck!