By far the most readily used Prover in the industry for many years. The Bi-Directional Pipe Prover Has proven itself over and over again as one of the most reliable means available to verify meterreadings and establish meter factors. It is still the most recommended and used Prover design inThe world today. By definition the Bi-Directional Pipe Prover is a positive displacement type prover with flow anddisplacer traveling in both directions by means of a 4-way diverter valve. The Bi-Directional Proveris constructed of pipe, which can be configured in many ways. Probably the most influentialadvantage of the Pipe Prover is its ability to allow the full flow of the stream through the meterbeing proved to pass through the prover. In this regard the Bi-Directional Pipe Prover offers ahistory of long-term reliability with minimum maintenance.