Mrs. Anderson's Disposable Dough Proofing Covers lock in moisture and maintain humidity for bread dough to rise and proof effectively. They easily seal proofing containers so dough won't dry out or form a skin' that can restrict dough from rising properly. Elastic closures hug proofing vessels to create an airtight fit for faster yeast fermentation. The round bowl covers fit most bowl sizes and shapes, up to 12-in. in diameter, while the large bags (18 x 25-in.) fit up to a full sheet pan. The transparent covers make it easy to monitor the proofing process at a quick glance. Made from BPA-free plastic, Mrs. Anderson's Mrs. Anderson's Dough Proofing Covers are durable, tear-resistant, include 50 bowl covers and 5 large tray bags with a resalable storage bag, and disposable for one-time use and easy cleanup.