This Royal Langnickel brush washer features a 3.75 - inch diameter. Its accordion - style sides collapse nearly flat for easy travel. You can expand it to full height and fill it with water for use.

Using this brush washer is super easy. First, expand it to its full height. Then, simply fill it with water. You can use it to wash your brushes as you would with any regular brush washer. When you're done traveling, collapse it almost flat for convenient storage. Just make sure to dry it thoroughly before storing to prevent mold. Also, avoid using harsh chemicals when cleaning it to keep it in good condition for a long time.