Not just for test tubes, the nylon bristles are great for cleaning all sorts of surfaces. It's also very flexible, you can bend it around for hard to reach places.

Main Color : Black;Brush Size : 2.5 x 0.8cm / 1" x 0.3" (L*Max.D) Handle Size : 7.5 x 0.4cm / 2.95" x 0.16" (L*D);Total Length : 10cm / 3.9" Net Weight : 13g Package Content : 10 x Test Tube Brush 10 x Black Plastic Handle 8mm Nylon Test Tube Clean Brush for Laboratory