His variation on the vest is backless. You can see other troopers wearing the same model of vest in the Gillette extended commercial but it's one of those blink and you miss it moments. My main question is what type of belt/attachment is used to secure both sides of the waist together.
He's wearing the Type 2 vest (with the Hoth Pack greeblie on the bottom right)
Full back.
I can't find any shots of the back but you can see it has a back on the ones at the Nissan display.
The backless one in the Gillette commercial is the Hoth vest.