Public domain photos

The image shows a small glass tube with a ruler next to it on a gray surface. The tube is made of glass and has text written on it. The ruler is placed next to the tube, suggesting that it is being used to measure the size of the tube.

The image shows a small glass tube with a ruler next to it on a gray surface. The tube is made of glass and has text written on it. The ruler is placed next to the tube, suggesting that it is being used to measure the size of the tube.Open in library