A sprinkler assembly comprising: a base including a passageway, an inlet opening communicating with a pressurized fluid source, an outlet opening for outputting a flow of pressurized fluid along a flow path, and an axis (z) extending through said outlet opening; a top extending from said base having a retaining ridge, said top and said base defining a cavity; a deployment assembly including a deflector ring disposed in the cavity and a pair of deflector pins supporting a flow shaper assembly, said deflector ring, said pair of deflector pins and said flow shaper assembly movably mounted relative to at least one of the base and the top and being movable horizontally between a retracted position and an extended position for dispersing the pressurized fluid from said outlet opening; a heat responsive trigger mounted to releasably retain said deflector pins and said flow shaper assembly within said retracted position, said flow shaper assembly having at least one contact surface for shaping the flow of pressurized fluid from said outlet opening when said deployment assembly is in said extended position, wherein said flow shaper assembly includes an opening aligned along said axis (z) extending through said outlet opening, said opening of said flow shaper assembly at least generally aligned along said flow path extending from said outlet opening along said axis (z), wherein fluid flows unimpeded through said opening of said flow shaper assembly, said flow shaper assembly having a flow shaper provided at said opening of said flow shaper assembly extending radially inward from a perimeter of said opening toward said axis (z); and a seat assembly disposed between said outlet opening and said flow shaper assembly, said seat assembly sealingly engaging said outlet opening to generally inhibit flow of said pressurized fluid when said deflector pins and said flow shaper assembly are in said retracted position, wherein said seat assembly is removable from said outlet opening in response to said movement of said deflector pins and said flow shaper assembly from said retracted position to said extended position wherein said seat assembly tumbles free from the sprinkler assembly. a base including a passageway, an inlet opening communicating with a pressurized fluid source, an outlet opening for outputting a flow of pressurized fluid along a flow path, and an axis (z) extending through said outlet opening; a top extending from said base having a retaining ridge, said top and said base defining a cavity; a deployment assembly including a deflector ring disposed in the cavity and a pair of deflector pins supporting a flow shaper assembly, said deflector ring, said pair of deflector pins and said flow shaper assembly movably mounted relative to at least one of the base and the top and being movable horizontally between a retracted position and an extended position for dispersing the pressurized fluid from said outlet opening; a heat responsive trigger mounted to releasably retain said deflector pins and said flow shaper assembly within said retracted position, said flow shaper assembly having at least one contact surface for shaping the flow of pressurized fluid from said outlet opening when said deployment assembly is in said extended position, wherein said flow shaper assembly includes an opening aligned along said axis (z) extending through said outlet opening, said opening of said flow shaper assembly at least generally aligned along said flow path extending from said outlet opening along said axis (z), wherein fluid flows unimpeded through said opening of said flow shaper assembly, said flow shaper assembly having a flow shaper provided at said opening of said flow shaper assembly extending radially inward from a perimeter of said opening toward said axis (z); and a seat assembly disposed between said outlet opening and said flow shaper assembly, said seat assembly sealingly engaging said outlet opening to generally inhibit flow of said pressurized fluid when said deflector pins and said flow shaper assembly are in said retracted position, wherein said seat assembly is removable from said outlet opening in response to said movement of said deflector pins and said flow shaper assembly from said retracted position to said extended position wherein said seat assembly tumbles free from the sprinkler assembly.