It's a 24" x 34" heavy mil, food-grade plastic bag. Anything you make with yeast, let it rise in a proofing bag. It's your answer to a baker's proofing box. It's like a mini greenhouse. Your bread will rise faster, higher.
"I made the [Sour Cream Onion] dough in my bread machine. It smelled so good while it was mixing. It tasted even better. I used half of the dough to make small slider/dollar rolls. I used the other half for regular-sized buns. So great as a small sandwich roll or with hamburgers."--Suzanne Jackson