Watts Drainage Products offers the "F" Series adjustable roof drain extension flanges. These flanges create a stable surface over deck openings, allowing roof drains to be mounted much more quickly. The non-corrosive, heavy gauge steel "F" flanges can function as both a sump receiver and adjustable extension, replacing traditional lightweight sump receivers and cumbersome, leak-prone threaded adjustable extensions. This series can be reversed for additional adjustment and special applications. Available with 12" and 15" diameter roof drain models. Watts Drainage Products.