progressive fluidics wr2 nozzles are designed for liquid fuel burners with continuously variable heat output. Inside the head is a special valve that regulates the flow of fuel passing through the nozzle depending on its pressure. Modulation burners operate in a wide range of capacities. The power of the burner is regulated smoothly using automation, which selects the correct ratio of air to fuel. To change the power of such a burner, nozzle change is not required.