Small plastic, bubbles in plastic = light reflection. I pay no attention to bubbles in baits I plan to use. The more reflection I can get from a bait the better.

I'm cooking off a box that had a little left in it and was in the garage until the other day when we went sub, sub zero. I'm sure there are some moisture balls rolling around in the remaining plastic...I know there are because I can hear them snapping in the microwave.