A spray nozzle (100, 200), comprising: a nozzle body (102, 202) having a proximal end (114, 214), a distal end (116, 216), a first through bore (118, 218) extending between the proximal and distal ends of the nozzle body, and an outer valve seat (120, 220) disposed at the distal end of the nozzle body; an inner valve seat (130, 260); an outer valve stem (104, 204) slidably disposed relative to the first through bore of the nozzle body and including a proximal end (124, 224), a distal end (126, 226), and an outer valve head (128, 228), the outer valve head carrying the inner valve seat (130, 260) at the distal end of the outer valve stem, and a second through bore (134, 234) extending through at least a distal portion of the outer valve stem, the outer valve head adapted to engage the outer valve seat of the nozzle body when the outer valve stem is in a closed position and adapted to be spaced away from the outer valve seat of the nozzle body when the outer valve stem is in an open position; an inner valve stem (106, 206) slidably disposed relative to the second through bore of the outer valve stem and including a proximal end (136, 236), a distal end (138, 238), and an inner valve head (140, 240) disposed at the distal end of the inner valve stem, the inner valve head adapted to engage the inner valve seat when the inner valve stem is in a closed position and adapted to be spaced away from the inner valve seat when the inner valve stem is in an open position; an outer bias device (108, 208) generating a first force biasing the outer valve head of the outer valve stem toward the outer valve seat of the nozzle body; and an inner bias device (110, 210) generating a second force biasing the inner valve head of the inner valve stem toward the inner valve seat of the outer valve stem, the spray nozzle being characterized in that it comprises a nozzle coupler having a proximal end, a distal end, and a third through bore extending between the proximal and distal ends of the nozzle coupler, the nozzle coupler being fixed in the second through bore (134, 234) of the outer valve stem (104, 204), wherein the third through bore slidably receives the inner valve stem (106, 206) and defines the inner valve seat (130, 260) at the distal end of the nozzle coupler; wherein the inner valve stem (106, 206) occupies the open position and the outer valve stem (104, 204) occupies the closed position upon the application of a first pressure on the distal ends of the inner and outer valve stems, and the inner and outer valve stems occupy the open positions upon the application of a second pressure that is greater than the first pressure on the distal ends of the inner and outer valve stems. a nozzle body (102, 202) having a proximal end (114, 214), a distal end (116, 216), a first through bore (118, 218) extending between the proximal and distal ends of the nozzle body, and an outer valve seat (120, 220) disposed at the distal end of the nozzle body; an inner valve seat (130, 260); an outer valve stem (104, 204) slidably disposed relative to the first through bore of the nozzle body and including a proximal end (124, 224), a distal end (126, 226), and an outer valve head (128, 228), the outer valve head carrying the inner valve seat (130, 260) at the distal end of the outer valve stem, and a second through bore (134, 234) extending through at least a distal portion of the outer valve stem, the outer valve head adapted to engage the outer valve seat of the nozzle body when the outer valve stem is in a closed position and adapted to be spaced away from the outer valve seat of the nozzle body when the outer valve stem is in an open position; an inner valve stem (106, 206) slidably disposed relative to the second through bore of the outer valve stem and including a proximal end (136, 236), a distal end (138, 238), and an inner valve head (140, 240) disposed at the distal end of the inner valve stem, the inner valve head adapted to engage the inner valve seat when the inner valve stem is in a closed position and adapted to be spaced away from the inner valve seat when the inner valve stem is in an open position; an outer bias device (108, 208) generating a first force biasing the outer valve head of the outer valve stem toward the outer valve seat of the nozzle body; and an inner bias device (110, 210) generating a second force biasing the inner valve head of the inner valve stem toward the inner valve seat of the outer valve stem, the spray nozzle being characterized in that it comprises a nozzle coupler having a proximal end, a distal end, and a third through bore extending between the proximal and distal ends of the nozzle coupler, the nozzle coupler being fixed in the second through bore (134, 234) of the outer valve stem (104, 204), wherein the third through bore slidably receives the inner valve stem (106, 206) and defines the inner valve seat (130, 260) at the distal end of the nozzle coupler; wherein the inner valve stem (106, 206) occupies the open position and the outer valve stem (104, 204) occupies the closed position upon the application of a first pressure on the distal ends of the inner and outer valve stems, and the inner and outer valve stems occupy the open positions upon the application of a second pressure that is greater than the first pressure on the distal ends of the inner and outer valve stems.