OPW Sight Flow Indicators are the most cost efficient and effective way to visually monitor the flow of fluids and to determine where, if any, problems exist at certain points along the industrial process line. Available in standard and high-pressure, high-temperature models, OPW Sight Flow Indicators incorporate an innovative radial seal for constant and uninterrupted sealing force between the body and the outside diameter of the glass lens, providing a longer lasting and better seal than conventional flat seals.