VENOAL 10 x Stainless Steel Twist Handle Nylon Test Tube Cleaning Brush White Not only for test tube, Nylon bristles are great to clean all surface types. Very flexible and can be bent around hard to reach places. Note: The color and size of the actual item may vary slightly from the color and size on the website due to lighting and display conditions. Also, since the size is measured by hand, there may be a margin of error of 0.4-1.2 inches