Based on the "Sirius" engine castings and sharing that engine's key dimensions, it features four rings per piston to avoid oil-contamination of the compressed air. The pumps were widely used in hospitals and laboratories.
| scale | 903 |
| length/inches | 6 |
| width/inches | 7 |
| height/inches | 7 |
| bore x stroke/inches | 1 x 1 |
| cylinder material | cast iron |