Six-port fuel valves are used where 2 tanks supply a single engine, and a return to each supply tank is required. ABYC H33.9.2 states that fuel system valves must have an independent means of support. That's why regular in-line valves are not appropriate for fuel systems applications. Provides flow to or from either of two connected tanks with its "L" shaped flow pattern and 180° handle actuation. NOT TO BE USED IN POTABLE WATER SYSTEMS.