The inexpensive Series 550 LP Valve is intended for low pressure meter mix applications. This manual valve is ideal for dispensing beads or RTM casting.
The design is simple: two ball valves are threaded into the back of the manifold and are connected to a common lever so that both valves open and close at the same time. (The 550 LP Valve is not intended for "feathering" or otherwise attempting to meter the flow.)