... . brass alloy, chrome plating 2.DN15, 1/2", DN20, 3/4 fire sprinkler,sprinkler head,fire nozzle1.ZSTZ-68oC to be installed upward ... , 2.ZSTX-68oC to be installed downward,3.ZSTBS-68oC to ... /4, flow coefficient 115,rated W.P. 1.2MPa. fire sprinkler