Backwater Valve Tutorial - Movies/Backwater-Valves-Explained.wmv -
Length: 1 minute (405K Media Player file)

Live Backwater Valve Demo - Movies/Backwater-Valve-Demo.wmv -
Length: 40 seconds (271K Media Player file).

Top Hinged Valves are prone to sludge buildup - Movies/Top-Hinged-Valve.wmv -
Length: 20 seconds (150K Media Player file)