Verification and/or checking the accuracy of  liquid meters can be done with a device known as a liquid displacement meter prover.  Meter provers can be stationary or mobile.  They can be bi-directional, uni-directional, piston type and small volume type. They are designed in accordance to the space available and the product to be proved, however, they must all be sized to accommodate the flow rates of the meters to be proved.

En-Fab, Inc. has designed, engineered,  manufactured and tested the various types of meter provers noted above. All En-Fab, Inc provers have their volumes certified by a third party and the calibration certificated are furnished to the client.

En-Fab provers are in accordance with, and will meet the standards set forth by the American Petroleum Institute (API) and the International Organization for Standardization (ISO).