These reusable holding bags are made of lightweight cotton, with a drawstring. Available in sizes 10x16, 8x12, and 6x8" (see drop down menu). They're perfect for use with our Pesola spring scales for getting bird weights, or for short term holding during examination, or banding. It's much easier to retrieve birds from these bags than to wrestle them out of hard crates where the potential for injury to the bird is much greater. These high quality bags will hold up to multiple washes.