Much Larger Than Expected
Bought the 156 and was able to fit a 156 K2 Ray-gun board with bindings attached, a holt helmet, EG2 goggle case, 2 size 10 boots, a shell jacket, an insulated jacket (that doesn't pack very well), dakine gloves, a small 11" x 5" bag with tools, insulated pants, and a couple beanies with a little bit of planning but not much effort.
On the downside, it doesn't have wheels so carrying all that on a strap is a pain. The other drawback for me is the clasps for the shoulder strap are all a hard plastic which doesn't feel cheap but makes me think it won't last very long given the weight i'm subjecting it to.
Overall for ~$60 - $70 depending on the sale it's a great option and I recommend it as long as you're ok with the possibility of having to replace the shoulder strap clasps in a couple years.