The open vessel option for MARS™ 6 allows researchers to use existing, conventional glassware in a scientific microwave. As the most cost-effective way to start performing microwave chemistry, the open vessel option permits easy access to the reaction solution for addition or removal of reaction solution, removal of gaseous by-products, application of non-ambient atmospheres, and mechanical stirring for viscous reactions. In addition, this option accommodates the largest reaction scale, fitting up to a 5-L round-bottom flask in the MARS 6 cavity. This means chemists can enjoy the flexibility of conventional glassware while benefiting from the heating advantages of microwave technology. CEM also offers 2 L and 4 L flow cell kits for continuous flow microwave-assisted synthesis.
| Maximum Capacity | Vessel Material | Vessel Volume | Maximum Temperature | Maximum Control Pressure |
| 1 Round Bottom Flask | Standard Glass | 250 mL - 5 L | Reflux (up to 300 °C) | N/A |
| 1 Flow Cell | Standard Glass | 2 L and 4 L | Reflux (up to 300 °C) | N/A |
