Manufactured in borosilicate glass with white enamel markings.
| Product | Tolerance | |
| Code | Description | ± ml |
| WJ.793 | Glass Parts only | 1 |
Usage Guide
Used for demonstrating respiration of germinating seeds such as peas or beans, or small animals like woodlice. The tube is filled with KOH solution which 
absorbs the carbon dioxide produced. The graduations show the percentage of the air that has been used – the oxygen content of the atmosphere.