Abstract: An improved spray nozzle assembly particularly adapted for use in dispersing cooling fluids onto the opposed relatively narrow sides of a pair of slabs in a split or twin cast continuous steel casting system. The discharging spray nozzle assembly is fashioned with a nozzle body having a manifold which is common to a plurality of transversely mounted spray nozzle heads. Each spray nozzle head has a plurality of closely spaced, slit-like discharge openings that communicate with the manifold via a barrel-like mixing chamber and internal flow passages, Each of the discharge openings on each of said spray nozzle heads has a specifically configured shape to facilitate an even distribution of coolant throughout a substantially rectangular spray pattern.