A heavy-duty, high-quality woven linen, 100cm x 70cm to support proving dough, especially baguettes or bâtons and lining proofing baskets. It helps give the dough a shape and wicks a little of the dough's outer moisture away to help develop a skin to help hold the final shape.
Linen is the best cloth fabric to use for proving dough as it has a lower tendency to stick to the dough. Dust with flour (preferably rye) to make sure that it doesn't stick.
When finished baking for the day, simply give the linen a good shake outside, or you can, if you prefer, just fold it up for next time. If you need to wash the couche linen, then wash in cold water.